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AVRHexFlashGUI: an AVRdude Hex Flasher GUI Application with Quick Flash Floating Button

Introduction

To program the AVR microcontroller you use “avrdude” to flash the hex files in the microcontroller. avrdude is a command line tool. Every time you have to flash the microcontroller with a new file you have to write the command.
This AVRHexFlashGUI uses the avrdude software to flash the microcontroller but it provides a Graphical User Interface.

There is a special feature I have implemented which is “QuickSet” Toolbar which has a “Quick FLASH” button. This toolbar floats on top of the screen. And provides an easy-to-use button for flashing the firmware files. It has an indicator that turns it’s color to green if the programming is successful or turns red if the programming is unsuccessful. It also has an ‘X’ button to switch off this toolbar.
Software such as microchip mplab x ide does not have an option to integrate the avrdude commands like in microchip studio(formerly Atmel Studio). This toolbar provides an easy access to flashing. You do not have to do anything else. Just launch the program and enable the QuickSet toolbar.

AVR microcontrollers are widely used in embedded systems development due to their versatility and ease of programming and also their low cost. Flashing firmware or code onto these microcontrollers is a fundamental task during development. The AVRHexFlashGUI is a graphical user interface (GUI) application built using the Tkinter library in Python.

Note: avrdude software must be installed on your system.
Download avrdude for windows https://github.com/avrdudes/avrdude/releases

Download

Screenshots

Overview

The AVRHexFlashGUI application streamlines the process of flashing firmware onto AVR microcontrollers using a user-friendly interface. It offers the following features:

  1. Microcontroller Selection: The application allows users to select the target microcontroller from a list of supported devices.
  2. Programmer Configuration: Users can specify the programmer to be used for flashing the firmware. This information is crucial for establishing a connection between the computer and the microcontroller.
  3. HEX File Selection: Users can browse their computer for the HEX file containing the firmware they want to flash onto the microcontroller.
  4. Quick Flash: The application provides a quick flash button that initiates the flashing process using the selected programmer, microcontroller, and HEX file.
  5. Read the Microcontroller Flash Memory: The user can read the unprotected flash memory and save it in the program folder as “HexFromDevice.hex”
  6. AVR Fuse Settings: The application offers the ability to read and display the current fuse settings of the connected AVR microcontroller. Users can also write new fuse settings if needed.
  7. Output Display: The application displays the output of the avrdude tool, which is responsible for flashing the firmware and handling the communication with the microcontroller.

Usage

To use the AVRHexFlashGUI application, follow these steps:

  1. Launch the application.
  2. Select the target microcontroller.
  3. Specify the programmer to be used for flashing.
  4. Load the desired HEX file by clicking the “Browse” button.
  5. Click the “Program AVR” button to start the flashing process.
  6. Monitor the avrdude output to ensure successful flashing.
  7. Optionally, use the “Fuse Setting” section to read, modify, and write fuse settings.
AVRHexFlash Quick Flash Toolbar with MPLAB X IDE

Conclusion

The AVRHexFlashGUI application simplifies the process of flashing firmware onto AVR microcontrollers by providing an intuitive and user-friendly interface. With features for microcontroller selection, programmer configuration, HEX file loading, and fuse settings, developers can efficiently program their microcontrollers. The use of Tkinter and Python makes it easy to create and customize the GUI, enhancing the overall user experience. This application is a valuable tool for both beginners and experienced developers working with AVR microcontrollers. By streamlining the flashing process, it helps save time and ensures accurate firmware deployment.

Read more: AVRHexFlashGUI: an AVRdude Hex Flasher GUI Application with Quick Flash Floating Button

Code

from tkinter import *
from tkinter import ttk
import serial
import serial.tools.list_ports
import datetime
import os
import sys
import subprocess
from tkinter import filedialog
# Get the directory of the script
script_dir = os.path.dirname(os.path.abspath(sys.argv[0]))

# Change the working directory to the script's directory
os.chdir(script_dir)
# For debug messages to be printed
dbg_msg = 0

root = Tk()
root.title("AVRHexFlashGUI")
root.resizable(False, False)  # Prevent window from being resized
sty = ttk.Style()
sty.theme_use("default")
#print(sty.theme_names())
root.columnconfigure(0, weight = 1)
root.rowconfigure(0, weight = 1)
# Frame Define START
Frame00 = ttk.LabelFrame(root, text = "AVRHexFlashGUI", padding = 10)
Frame00.grid(column = 0, row = 0, sticky =  (W,E) )
Frame01 = ttk.LabelFrame(root, text = "Fuse Setting", padding = 10)
Frame01.grid(column = 2, row = 0, sticky =  (W,E) )
## Frame Define START
canvas = None
circle = None
# Frame00 START
label0011 = ttk.Label(Frame00, text = "Microcontroller")
label0011.grid(column = 0, row = 0, sticky = (N,E,W,S))

MCU_save_stored_value = StringVar()
MCU_save_stored_value_display = Text(Frame00, height = 1, width = 2, wrap=WORD)
MCU_save_stored_value_display.grid(row = 0, column = 1, sticky = (N,E,W,S))
# Display the file value
file_path = os.path.join("Data", "MCU_save.txt")
if os.path.exists(file_path):
    with open(file_path, 'r') as file:
        MCU_value = file.read()
        MCU_save_stored_value_display.insert(END, MCU_value)

programmer_label = ttk.Label(Frame00, text="Programmer:")
programmer_label.grid(row = 0, column  = 2, sticky = (N,E,W,S))
programmer_var = StringVar()
programmer_var_display = Text(Frame00, height = 1, width = 10, wrap=WORD)
programmer_var_display.grid(row = 0, column = 3, sticky = (N,E,W,S))
# Display the file value
file_path = os.path.join("Data", "avrdude_programmer.txt")
if os.path.exists(file_path):
    with open(file_path, 'r') as file:
        Prog_value = file.read()
        programmer_var_display.insert(END, Prog_value)


label0010 = ttk.Label(Frame00, text="Select HEX File:")
label0010.grid(row = 1, column  = 0, sticky = (N,E,W,S))
hex_file_path = StringVar()
hex_file_path.set("Load your File")

def browse_file():
    file_path = filedialog.askopenfilename(filetypes=[("HEX Files", "*.hex")])
    if file_path:
        hex_file_path.delete(1.0, END)  # Clear previous text
        hex_file_path.insert(END, file_path)
        hex_file_path.config(wrap=WORD)  # Enable text wrapping

    new_complete_command = ">> avrdude " + "-c " + programmer_var_display.get('1.0', 'end-1c') \
                           + " -p " + MCU_save_stored_value_display.get('1.0', 'end-1c') \
                           + " -U " + "flash:w:" + hex_file_path.get('1.0', 'end-1c') + ":i"
    complete_command_var.set(new_complete_command)

def copy_to_clipboard():
    start_index = hex_file_path.index(SEL_FIRST)
    end_index = hex_file_path.index(SEL_LAST)
    
    if start_index and end_index:
        selected_text = hex_file_path.get(start_index, end_index)
        root.clipboard_clear()
        root.clipboard_append(selected_text)
        root.update()
def save_to_file():
    file_path = os.path.join("Data", "Hex_save_location.txt")
    with open(file_path, 'w') as file:
        file.write(hex_file_path.get('1.0', 'end-1c'))
    file_path = os.path.join("Data", "avrdude_programmer.txt")
    with open(file_path, 'w') as file:
        file.write(programmer_var_display.get('1.0', 'end-1c'))
    file_path = os.path.join("Data", "MCU_save.txt")
    with open(file_path, 'w') as file:
        file.write(MCU_save_stored_value_display.get('1.0', 'end-1c'))

def getMcuList():    
    prog_name = programmer_var_display.get('1.0','end-1c')
    command = ['avrdude','-c',prog_name]
    result = subprocess.run(command, shell=True, capture_output=True, text=True)
    
    output_lines = result.stderr.split('\n')
    for line in output_lines:
        display_avrdude_output.insert(END, line + '\n')
    display_avrdude_output.see("end")

def DumpHex():    
    prog_name = programmer_var_display.get('1.0','end-1c')
    part_name = MCU_save_stored_value_display.get('1.0','end-1c')
    command = ['avrdude','-c',prog_name,'-p',part_name,'-U', 'flash:r:HexFromDevice.hex:i']
    result = subprocess.run(command, shell=True, capture_output=True, text=True)
    display_avrdude_output.delete('1.0',END)
    output_lines = result.stderr.split('\n')
    for line in output_lines:
        display_avrdude_output.insert(END, line + '\n')
    display_avrdude_output.see("end")    
    
button0011 = ttk.Button(Frame00, text="Browse", command=browse_file)
button0011.grid(row = 1, column  = 1,sticky = (N,E,W,S))

McuListbutton = ttk.Button(Frame00, text="Get Supported\nMCU List", command=getMcuList)
McuListbutton.grid(row = 1, column  = 3,sticky = (N,E,W,S))
DumpHexbutton = ttk.Button(Frame00, text="Read Device\nSave File", command=DumpHex)
DumpHexbutton.grid(row = 1, column  = 2,sticky = (N,E,W,S))

hex_file_path = Text(Frame00, height=5, width=50, wrap=WORD)
hex_file_path.grid(row=2, column=0, columnspan=2, sticky=(N,E,W,S))
# Display the file value
file_path = os.path.join("Data", "Hex_save_location.txt")
if os.path.exists(file_path):
    with open(file_path, 'r') as file:
        Hex_file_value = file.read()
        hex_file_path.insert(END, Hex_file_value)
# Bind right-click context menu to hex_file_path
context_menu = Menu(hex_file_path, tearoff=0)
context_menu.add_command(label="Copy", command=copy_to_clipboard)
hex_file_path.bind("<Button-3>", lambda event: context_menu.post(event.x_root, event.y_root))
button_save = ttk.Button(Frame00, text="Save to File", command=save_to_file)
button_save.grid(row=5, column=0, sticky=(N,E,W,S))


complete_command_var = StringVar()
Complete_Command = ">> avrdude "+"-c "+programmer_var_display.get('1.0','end-1c') \
                   +" -p "+MCU_save_stored_value_display.get('1.0','end-1c')\
                   +" -U "+"flash:w:"+hex_file_path.get('1.0','end-1c')+":i"
complete_command_var.set(Complete_Command)
display_complete_command = ttk.Label(Frame00, wraplength=500, textvariable= complete_command_var)
display_complete_command.grid(row=4, column=0, sticky=(N,E,W,S))


def program_avr():
    display_avrdude_output.delete('1.0',END)
    prog_name = programmer_var_display.get('1.0','end-1c')
    part_name = MCU_save_stored_value_display.get('1.0','end-1c')
    hex_file_address = hex_file_path.get('1.0','end-1c')
    flash_statement = "flash:w:"+hex_file_address+":i"
    
    command = ['avrdude','-c',prog_name,'-p',part_name,'-U',flash_statement]
    print(command)
    
    result = subprocess.run(command, shell=True, capture_output=True, text=True)
    
    # Analyze the result and indicate success or failure
    output_lines = result.stderr.split('\n')
    success_indication = "flash verified\n\navrdude done.  Thank you."
    success_indication_1 = "flash verified\n\navrdude: safemode: Fuses OK\n\navrdude done.  Thank you."
    success = success_indication in result.stderr or success_indication_1 in result.stderr

    for line in output_lines:
        display_avrdude_output.insert(END, line + '\n')

    display_avrdude_output.see("end")

    if success:
        print("Programming successful!")
        try:
            canvas.itemconfig(circle, fill='#aaff00')
        except:
            pass
        
    else:
        print("Programming failed.")
        try:
            canvas.itemconfig(circle, fill='red')
        except:
            pass
        

sty.configure("Color.TButton", background="blue", foreground="white")
button0021 = ttk.Button(Frame00,style='Color.TButton', text="Program AVR", command=program_avr)
button0021.grid(row = 5, column  = 1)

display_avrdude_output = Text(Frame00, height=10, width=50, wrap=WORD)
display_avrdude_output.grid(row=6, columnspan=4, sticky=(N,E,W,S))
scrollbar = Scrollbar(Frame00, command=display_avrdude_output.yview)
scrollbar.grid(row=6, column=4, sticky=(N, S))
display_avrdude_output.config(yscrollcommand=scrollbar.set)

Abhay_text = "This program is writtent by : ABHAY KANT\nvisit: https://exasub.com"
AbhayLabel = ttk.Label(Frame00, text=Abhay_text)
AbhayLabel.grid(row = 11, column  = 0, sticky = (N,E,W,S))
## Frame00 END

def donothing():
   filewin = Toplevel(root)
   button = Button(filewin, text="Do nothing button")
   button.pack()

about_window = None  
def About_me():
    global about_window
    
    if about_window is None or not about_window.winfo_exists():
        about_window = Toplevel(root)
        about_window.title("About Me")
        
        label1 = ttk.Label(about_window, text="EXASUB.COM")
        label1.pack()
        
        button = ttk.Button(about_window, text="Quit", command=about_window.destroy)
        button.pack()
    else:
        about_window.lift()  

hfuse_read_value_display = None
lfuse_read_value_display = None
def Read_fuse():
    hfuse_read_value_display.delete('1.0',END)
    lfuse_read_value_display.delete('1.0',END)
    prog_name = programmer_var_display.get('1.0','end-1c')
    part_name = MCU_save_stored_value_display.get('1.0','end-1c')
    
    hfuse_statement = "hfuse:r:-:h"
    lfuse_statement = "lfuse:r:-:h"
    
    command = ['avrdude','-c',prog_name,'-p',part_name,'-U',hfuse_statement]
    result = subprocess.run(command, shell=True, capture_output=True, text=True)
    hfuse_read_value_display.insert(END,result.stdout)
    
    command = ['avrdude','-c',prog_name,'-p',part_name,'-U',lfuse_statement]
    result = subprocess.run(command, shell=True, capture_output=True, text=True)
    lfuse_read_value_display.insert(END,result.stdout)

    
fusesetwin = None
fusesetwin_write = None
def FuseSet():
    global fusesetwin,hfuse_read_value_display,lfuse_read_value_display
    if fusesetwin is None or not fusesetwin.winfo_exists():
            
        fusesetwin = Toplevel(root)
        
        button = Button(fusesetwin, text="Quit", command = fusesetwin.destroy)
        button.grid(column = 0, row = 0, sticky = (N,E,W,S))
        Read_Fuse_label = ttk.Label(fusesetwin, text="Read Fuse Values")
        Read_Fuse_label.grid( row = 1,column = 0, sticky = (N,E,W,S))

        read_fuse_button = Button(fusesetwin, text="Read", command = Read_fuse)
        read_fuse_button.grid(column = 1, row = 1, sticky = (N,E,W,S))

        hFuse_label = ttk.Label(fusesetwin, text="hFuse ")
        hFuse_label.grid( row = 2,column = 0, sticky = (N,E,W,S))
        hfuse_read_value_display = Text(fusesetwin, height = 1, width = 6, wrap=WORD)
        hfuse_read_value_display.grid(row = 2, column = 1, sticky = (N,E,W,S))

        lFuse_label = ttk.Label(fusesetwin, text="lFuse ")
        lFuse_label.grid( row = 3,column = 0, sticky = (N,E,W,S))
        lfuse_read_value_display = Text(fusesetwin, height = 1, width = 6, wrap=WORD)
        lfuse_read_value_display.grid(row = 3, column = 1, sticky = (N,E,W,S))
        # Separator object
        separator = ttk.Separator(fusesetwin, orient='horizontal')
        separator.grid(column = 0,columnspan=2, row = 4, sticky = (N,E,W,S))
            
        
        
        
        def fuseWrite():
            global fusesetwin_write
            if fusesetwin_write is None or not fusesetwin_write.winfo_exists():
                fusesetwin_write = Toplevel(root)
                label0101 = ttk.Label(fusesetwin_write, text = "Stored Default Fuse Settings")
                label0101.grid(column = 0, row = 0, sticky = (N,E,W,S))

                label0110 = ttk.Label(fusesetwin_write, text = "hFuse")
                label0110.grid( row = 1,column = 0, sticky = (N,E,W,S))
                hfuse_stored_value = StringVar()
                hfuse_stored_value_display = Text(fusesetwin_write, height = 1, width = 6, wrap=WORD)
                hfuse_stored_value_display.grid(row = 1, column = 1, sticky = (N,E,W,S))
                # Display the file value
                file_path = os.path.join("Data", "Fuse_hfuse.txt")
                if os.path.exists(file_path):
                    with open(file_path, 'r') as file:
                        fuse_value = file.read()
                        hfuse_stored_value_display.insert(END, fuse_value)


                label0120 = ttk.Label(fusesetwin_write, text = "lFuse")
                label0120.grid( row = 2,column = 0, sticky = (N,E,W,S))
                lfuse_stored_value = StringVar()
                lfuse_stored_value_display = Text(fusesetwin_write, height = 1, width = 6, wrap=WORD)
                lfuse_stored_value_display.grid(row = 2, column = 1, sticky = (N,E,W,S))
                # Display the file value
                file_path = os.path.join("Data", "Fuse_lfuse.txt")
                if os.path.exists(file_path):
                    with open(file_path, 'r') as file:
                        fuse_value = file.read()
                        lfuse_stored_value_display.insert(END, fuse_value)
                def flashfuse():
                    
                    prog_name = programmer_var_display.get('1.0','end-1c')
                    part_name = MCU_save_stored_value_display.get('1.0','end-1c')
                    
                    hfuse_statement = "hfuse:w:"+hfuse_stored_value_display.get('1.0', 'end-1c')+":m"
                    lfuse_statement = "lfuse:w:"+lfuse_stored_value_display.get('1.0', 'end-1c')+":m"
                    print(hfuse_statement)
                    print(lfuse_statement)
                    command = ['avrdude','-c',prog_name,'-p',part_name,'-U',hfuse_statement]
                    result = subprocess.run(command, shell=True, capture_output=True, text=True)
                    
                    output_lines = result.stderr.split('\n')
                    success_indication = "flash verified\n\navrdude done.  Thank you."
                    success = success_indication in result.stderr

                    for line in output_lines:
                        display_avrdude_output.insert(END, line + '\n')

                    display_avrdude_output.see("end")

                    if success:
                        print("Programming successful!")
                        try:
                            canvas.itemconfig(circle, fill='#aaff00')
                        except:
                            pass
                        
                    else:
                        print("Programming failed.")
                        try:
                            canvas.itemconfig(circle, fill='red')
                        except:
                            pass
                        
                    
                    command = ['avrdude','-c',prog_name,'-p',part_name,'-U',lfuse_statement]
                    result = subprocess.run(command, shell=True, capture_output=True, text=True)
                    
                    output_lines = result.stderr.split('\n')
                    success_indication = "flash verified\n\navrdude done.  Thank you."
                    success = success_indication in result.stderr

                    for line in output_lines:
                        display_avrdude_output.insert(END, line + '\n')

                    display_avrdude_output.see("end")

                    if success:
                        print("Programming successful!")
                        try:
                            canvas.itemconfig(circle, fill='#aaff00')
                        except:
                            pass
                        
                    else:
                        print("Programming failed.")
                        try:
                            canvas.itemconfig(circle, fill='red')
                        except:
                            pass
                        
                
                WriteFusebutton = Button(fusesetwin_write,text="Write Fuse", command = flashfuse)
                WriteFusebutton.grid(row = 0, column=1, sticky= (N,W,E,S))
                NoteLabelText = "Note: Change the  fuse setting carefully. \
                                \nPlease check the datasheet for correct fuse setting \
                                \nWrong Fuse setting may disable programming using programmer\
                                \nIf programmer is disabled you will need the offical ATMEL programmer"
                NoteLabel = ttk.Label(fusesetwin_write, wraplength = 500, text = NoteLabelText)
                NoteLabel.grid(column = 0, columnspan = 2, row = 10, sticky = (N,E,W,S))
            else:
                fusesetwin_write.lift()
        Write_Fuse_button = Button(fusesetwin, text="Write Fuse", command = fuseWrite)
        Write_Fuse_button.grid(column = 0,row = 5, sticky = (N,E,W,S))
    else:
         fusesetwin.lift()

quicksetwin = None
startx = 0
starty = 0

def move_window(event):
    global startx, starty
    x = quicksetwin.winfo_pointerx() - startx
    y = quicksetwin.winfo_pointery() - starty
    quicksetwin.geometry(f"+{x}+{y}")
    startx = quicksetwin.winfo_pointerx() - x
    starty = quicksetwin.winfo_pointery() - y


def Quick_set():
    global quicksetwin, startx, starty, circle,canvas
    if quicksetwin is None or not quicksetwin.winfo_exists():
        quicksetwin = Toplevel(root)
        quicksetwin.attributes("-topmost", True)  # Set the window to stay on top
        quicksetwin.overrideredirect(True)  # Remove window decorations
        
        title_bar = Frame(quicksetwin, bg="gray", relief="raised", bd=2)
        title_bar.grid(column=0, row=0, columnspan=3, sticky=(N, E, W))
        title_bar.bind("<ButtonPress-1>", start_move)
        title_bar.bind("<B1-Motion>", move_window)
        
        quickbutton = Button(title_bar, text="X", command=quicksetwin.destroy)
        quickbutton.grid(column=3, row=0, sticky=(N, E, W))
        
        quickProgbutton = Button(title_bar, text="Quick FLASH", command=program_avr)
        quickProgbutton.grid(column=1, row=0, sticky=(N, E, W), padx=5)
        global circle,canvas
        canvas = Canvas(title_bar, width=20, height=20)
        canvas.grid(column=2, row=0, sticky=(N, E, W), padx=5)

        # Draw a circle initially with a default color
        circle = canvas.create_oval(2, 2, 19, 19, fill='gray')
        
    else:
        quicksetwin.lift()

def start_move(event):
    global startx, starty
    startx = event.x
    starty = event.y



menubar = Menu(root)

Fusemenu = Menu(menubar, tearoff=1)
menubar.add_cascade(label="Fuse Setting", command=FuseSet)


menubar.add_command(label = "EXASUB.com", command = About_me)

menubar.add_command(label = "Quit", command = root.destroy)
menubar.add_command(label = "QuickSet", command = Quick_set)
root.config(menu=menubar)
if __name__ == "__main__":
    root.mainloop()
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ATmega328PB 16-bit Timer TC3 – Fast PWM Mode

1 millisecond pulse width
50 Hz Frequency
1.5 millisecond pulse width
50 Hz Frequency
2 millisecond pulse width
50 Hz Frequency

I have used this FAST PWM mode to trigger two interrupt service routines.
The timer compares register A sets the frequency.
I have not enabled the output compare pins. since it was used by some other peripheral. So by doing this, I generate a PWM signal by issuing a command in the ISR.

/*
* main.c
*
* Created: 10 July 2023 10:47:23 PM
*  Author: abhay
*/
#define F_CPU 16000000

#include <xc.h>
#include <stdio.h>
#include "util/delay.h"
#include <avr/interrupt.h>
#include "uart.h"
#define LED_ON PORTB |= (1<<5)
#define LED_OFF PORTB &= ~(1<<5)


// Function to send a character via UART
int UART_putchar(char c, FILE *stream) {
	if (c == '\n')
	UART_putchar('\r', stream);  // Add carriage return before newline
	while (!(UCSR0A & (1 << UDRE0))); // Wait for the transmit buffer to be empty
	UDR0 = c; // Transmit the character
	return 0;
}

// Create a FILE structure to redirect the printf stream to UART
FILE uart_output = FDEV_SETUP_STREAM(UART_putchar, NULL, _FDEV_SETUP_WRITE);

ISR(TIMER3_COMPA_vect){
	PORTD |= (1<<6);
}
ISR(TIMER3_COMPB_vect){
	PORTD &= ~(1<<6);
	
}

int main(void)
{
	

	USART_Init();
	// Redirect stdout stream to UART
	stdout = &uart_output;
	DDRB |= (1<<5);	// set Data direction to output for PB5
	LED_OFF; // set output to high
	DDRD |= (1 << 6);	//set PD6 as output
	
	
	/*
	F_CPU = 16000000
	Prescaler = 64
	Frequency = 50Hz
	Period = 0.020 s
	step time = 1/(F_CPU/Prescaler) = 0.000004 s
	number of steps = 0.020/0.000004 = 5000
	*/
	TCNT3 = 0;		// Timer counter initial value = 0
	// Output Compare A value = 5000 or 20 Milli second
	OCR3A = 5000;
	// Output Compare B value = 500 or 2 Milli second 
	OCR3B = 500;	
	// Fast PWM
	TCCR1A |= (1 << WGM31)|(1 << WGM30);	
	//  Prescaler: 64
	TCCR3B |= (1 << WGM32)|(1<<WGM32)|(1 << CS31)|(1 << CS30);	
	// Enable Timer Interrupt for Overflow, Compare match A and Compare Match B
	TIMSK3 |= (1 << OCIE3B)|(1 << OCIE3A)|(1<<TOIE3);	 
	
	// Enable Global Interrupt
	sei();	
	
	while(1)
	{
		OCR3B = 250;//5% 1ms
		_delay_ms(500);
		OCR3B = 375;//7.5% 1.5ms
		_delay_ms(100);
		OCR3B = 500;//10% 2ms
		_delay_ms(500);

	}
	
	
}
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ATmega328PB 16-bit Timer TC1 – CTC Mode

Timers are essential components in microcontrollers that allow precise timing and synchronization for various applications. The ATmega328PB microcontroller offers several timer/counters, including Timer/Counter 1 (TC1), which is a 16-bit timer with advanced features. In this blog post, I will explore how to utilize Timer 1 in CTC (Clear Timer on Compare Match) mode on the ATmega328PB microcontroller.

Hardware Setup

Before we proceed with the code, ensure you have the necessary hardware setup. You will need an ATmega328PB microcontroller, a 16MHz crystal oscillator, and any additional components required for your specific application. Connect the crystal oscillator to the XTAL1 and XTAL2 pins of the microcontroller to provide a stable clock signal.

UART Communication Initialization

In this example, we will utilize UART communication for debugging or output purposes. Make sure you have already implemented the necessary UART functions or library. The UART initialization code should include setting the baud rate, enabling the transmitter and receiver, and configuring the data format (e.g., number of data bits, parity, and stop bits). We will also redirect the stdout stream to the UART using the stdio.h library, allowing us to use the printf function for UART output.

Timer 1 Configuration in CTC Mode

Let’s dive into the code and configure Timer 1 in CTC mode. Here’s an example code snippet:

/*
* main.c
*
* Created: 7/9/2023 12:47:23 AM
*  Author: abhay
*/
#define F_CPU 16000000

#include <xc.h>
#include <stdio.h>
#include "util/delay.h"
#include <avr/interrupt.h>
#include "uart.h"

// Function to send a character via UART
int UART_putchar(char c, FILE *stream) {
	if (c == '\n')
	UART_putchar('\r', stream);  // Add carriage return before newline
	while (!(UCSR0A & (1 << UDRE0))); // Wait for the transmit buffer to be empty
	UDR0 = c; // Transmit the character
	return 0;
}

// Create a FILE structure to redirect the printf stream to UART
FILE uart_output = FDEV_SETUP_STREAM(UART_putchar, NULL, _FDEV_SETUP_WRITE);
ISR(TIMER1_COMPA_vect){
	printf("2. compare match A\n");
}
ISR(TIMER1_COMPB_vect){
	printf("1. compare match B\n");
}
int main(void)
{
	USART_Init();
	// Redirect stdout stream to UART
	stdout = &uart_output;
	DDRB |= (1<<5);	// set Data direction to output for PB5
	PORTB |= (1<<5); // set output to high
	/*
	* Timer 1 
	* Mode of operation : CTC
	*		When Output Compare A register value equals the 
	*		Timer Counter register (TCNT1) it resets the Timer-Counter-register value
	*		and generates a interrupt. 
	* Only OCR1A will reset the timer counter. 
	* OCR1B can be used to generate a compare match between TCNT1 = 0 and OCR1A
	*
	*/
	TCNT1 = 0;		// Timer counter initial value = 0
	OCR1BH = 0x3D;	// Output Compare B value = 0x3d09 or 1 second
	OCR1BL = 0x09;
	OCR1AH = 0x7a;	// Output Compare A value = 0x7a12 or 2 second
	OCR1AL = 0x12;
	TCCR1B |= (1<<WGM02)|(1 << CS12)|(1 << CS10);	// CTC Prescaler: 1024
	TIMSK1 |= (1 << OCIE1B)|(1 << OCIE1A)|(1<<TOIE1);
	
	sei();	// Enable Global Interrupt
	while(1)
	{

		
		printf("  This is Main:\n");
 		_delay_ms(2500);
	
		//TODO:: Please write your application code
		
	}
}

In this code snippet, we first initialize the UART communication and redirect the stdout stream to the UART output using the FDEV_SETUP_STREAM macro. The UART_putchar function is used to send a character via UART, ensuring that newline characters (\n) are preceded by a carriage return character (\r) for proper line endings.

Next, we configure Timer/Counter 1 (TC1) for CTC mode and set the prescaler to 1024, which divides the clock frequency to generate a suitable timebase. The TCCR1A and TCCR1B registers are set accordingly.

We then set the compare values (OCR1A and OCR1B) to determine the time intervals at which we want to generate interrupts. In this example, OCR1A is set for 2 second delay, and OCR1B is set for approximately 1 seconds delay.

Finally, we enable the Timer/Counter TC1 compare match interrupts (OCIE1A and OCIE1B) using the TIMSK1 register, and we enable global interrupts with the sei() function.

Interrupt Service Routines (ISRs)

The code snippet defines two Interrupt Service Routines (ISRs): TIMER1_COMPA_vect and TIMER1_COMPB_vect. These ISRs will be executed when a compare match occurs for Output Compare A and Output Compare B, respectively. In this example, we use these ISRs to print messages to the UART output. You can modify these ISRs to perform any desired actions based on your specific application requirements.

Putting It All Together

Once you have set up the UART communication, configured Timer 1 in CTC mode, and defined the necessary ISRs, you can utilize the precise timing capabilities of Timer 1 in your main program loop. Use the printf function to output information via UART, and the compare match interrupts will handle the precise timing events.

while (1) {
   printf("  This is Main:\n");
 		_delay_ms(2500);
    // Additional code and operations
    // ...
}

In the above example, the main program loop will execute continuously, printing “This is the main program loop” every 1 second using the printf function. The _delay_ms function provides a delay of 2500 milliseconds (2.5 second) between each iteration of the loop.

Conclusion

Utilizing Timer 1 in CTC mode on the ATmega328PB microcontroller provides precise timing capabilities for various applications. By configuring Timer 1, setting compare match values, and utilizing compare match interrupts, you can achieve accurate timing control in your embedded systems. When combined with UART communication, you can easily monitor and debug your code by printing relevant information via the UART interface.

Remember to consult the ATmega328PB datasheet and relevant documentation for more details on Timer 1, CTC mode, and other timer features. Ensure that you have correctly configured your hardware setup, including the crystal oscillator and UART connection, to match the code requirements.

Using Timer 1 in CTC mode

with UART communication opens up a range of possibilities for precise timing and debugging capabilities in your projects. Experiment with different compare match values and integrate this functionality into your applications to enhance timing accuracy and control.

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ATmega328PB 8-Bit Timer TC0 – Normal Mode

The simplest mode of operation is the Normal mode (WGM0[2:0] = 0x0). In this mode, the counting direction is always up (incrementing), and no counter clear is performed. The counter simply overruns when it passes its maximum 8-bit value (TOP=0xFF) and then restarts from the bottom (0x00). In Normal mode operation, the Timer/Counter Overflow flag (TOV0) will be set in the same clock cycle in which the TCNT0 becomes zero. In this case, the TOV0 flag behaves like a ninth bit, except that it is only set, not cleared. However, combined with the timer overflow interrupt that automatically clears the TOV0 flag, the timer resolution can be increased by software. There are no special cases to consider in the Normal
mode, a new counter value can be written any time.

The output compare unit can be used to generate interrupts at some given time. Using the output compare to generate waveforms in Normal mode is not recommended since this will occupy too much of the CPU time.

The counter will always count from 0 to 255 and then after 255 it will set the overflow bit and start the counting from 0.

Without Interrupt

We can use this to generate delays. But This is a type of blocking code.

/*
 * main.c
 *
 * Created: 7/9/2023 12:47:23 AM
 *  Author: abhay
 */ 
#define F_CPU 16000000UL
#include <xc.h>

#include <util/delay.h>
void T0delay();
int main(void)
{
	DDRB |= (1<<5);
	PORTB |= (1<<5);
    while(1)
    {
		PORTB |= (1<<PINB5);
		T0delay();
		PORTB &= ~(1<<PINB5);
                T0delay();
		//TODO:: Please write your application code 
		
    }
}
void T0delay()
{
	/*
	F_CPU/prescaler = clock for timer
	1/clock for timer = timer step time
	for 1 second the timer will take : 1/timer step time
	
	16000000/1024 = 15625 clock
	1/15625 = 0.000064 = 64us	(counter step size)
	64us x 256 = 0.016384 sec (0verflow time)
	64us x 255 - tcnt +1 = 0.016384 sec (0verflow time)
		64us x (255 - tcnt +1 )= x
		tcnt = x / 64us ) -256
		
	for 1 sec Delay
	=> 1/0.016384 sec = 61.03515625
	Taking only integer 
	so 61 overflows needs to occur for 0.999424 Seconds
	1-0.999424 = 0.000576 seconds
	0.000576/ (counter step size) = required steps 
	0.000576/0.00064 = 9 steps
	Note: this will be close to 1 second. but it will be longer due to overhead added by the instructions.
	*/
	for(int i = 0; i< 61;i++){
	TCNT0 = 0;
	TCCR0A = 0;
	TCCR0B |= (1<<CS00)|(1<<CS02);	//prescaler 1024
	while( (TIFR0 & 0x1) == 0);	// Wait for overflow flag
	TCCR0B = 0;
	TIFR0 = 0x1;
	}
	//9 steps timer code
	TCNT0 = 255-9;
	TCCR0A = 0;
	TCCR0B |= (1<<CS00)|(1<<CS02);	//prescaler 1024
	while( (TIFR0 & 0x1) == 0);	// Wait for overflow flag
	TCCR0B = 0;
	TIFR0 = 0x1;
}

Normal Mode with Interrupt

#define F_CPU 16000000UL
#include <xc.h>
#include <avr/interrupt.h>
ISR(TIMER0_OVF_vect){
	PORTB ^= (1<<PINB5);   // Toggle the GPIO
}
int main(void)
{
	
	DDRB |= (1<<5);	// set Data direction to output for PB5
	PORTB |= (1<<5);    // set output to high
	
	TCNT0 = 0;
	TCCR0A = 0;     // Normal Mode
	TCCR0B |= (1<<CS00)|(1<<CS02);	//prescaler 1024
	TIMSK0 |= (1 << TOIE0);	// Overflow Interrupt Enable Bit
	
	sei();	// Enable Global Interrupt
	while(1)
	{
		//TODO:: Please write your application code
		
	}
}

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How to use S109AFTG Microstep Driver with ATmega328PB Programmed using Microchip Studio

When I opened the case. I found a PCB which is screwed to a big heatsink. I unscrewed the bolts and saw that there is S109AFTG. The IC is sandwiched between the PCB and the heatsink. A small aluminum block is also used for heat transfer between the IC and the heatsink.

It has a different step size which can be selected by the DIP switches.
The motor driver has a maximum of 1/32 step size.

which means 1.8°/ 32 = 0.05625°

360°/ 0.05625° = 6400 steps

So a full rotation will be in 6400 steps.

You will need a power source such as a Switched Mode Power Supply which can supply at least 2 Amps.

If your application needs more torque you will need a power source that can provide a high current without dropping the voltage.

Or you can use the battery for a short duration.

Schematic Diagram

Code

/*
* main.c
*
* Created: 7/4/2023 5:51:21 PM
*  Author: abhay
*/
#define F_CPU 16000000
#include <xc.h>
#include <util/delay.h>
int PUL=PIND6; //define Pulse pin
int DIR=PINB1; //define Direction pin
int ENA=PIND2; //define Enable Pin
#define DirLow PORTB &= ~(1<<DIR)
#define DirHigh PORTB |= (1<<DIR)
#define PulLow PORTD &= ~(1<<PUL)
#define PulHigh PORTD |= (1<<PUL)
#define EnaLow PORTD &= ~(1<<ENA)
#define EnaHigh PORTD |= (1<<ENA)
#define delayus50 _delay_us(50)
int main(void)
{
	DDRB |= (1<<DIR);
	DDRD |= (1<<PUL)|(1<<ENA);
	while(1)
	{
		//TODO:: Please write your application code
		for (int i=0; i<6400; i++)    //Forward 6400 steps
		{
			DirLow;
			EnaHigh;
			PulHigh;
			delayus50;
			PulLow;
			delayus50;
		}
		_delay_ms(5000);
		for (int i=0; i<6400; i++)   //Backward 6400 steps
		{
			DirHigh;
			EnaHigh;
			PulHigh;
			delayus50;
			PulLow;
			delayus50;
		}
		_delay_ms(2000);
	}
}
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What are AVR microcontrollers?

AVR microcontrollers, developed by Atmel Corporation (now Microchip Technology), are designed for embedded applications that require low power consumption, high performance, and a small footprint. The AVR family includes a range of microcontrollers, each with varying processing power, memory capacity, and peripheral features.

  • ATmega series: This popular series of 8-bit AVR microcontrollers offers up to 256KB of flash memory, 16-channel 10-bit ADC, and up to 86 general-purpose I/O pins.
    • Example: ATmega328P, which is commonly used in the Arduino Uno board. It has 32KB of flash memory, 2KB of SRAM, and 1KB of EEPROM.
  • ATtiny series: This low-power, low-cost series of 8-bit AVR microcontrollers is ideal for simple applications that require basic processing and control functions. They typically have less flash memory and fewer peripheral features compared to the ATmega series.
    • Example: ATtiny85, which is commonly used in the Digispark development board. It has 8KB of flash memory, 512 bytes of SRAM, and 512 bytes of EEPROM.
  • ATxmega series: This series of 8/16-bit AVR microcontrollers offers higher processing power, more memory, and advanced features such as DMA, DAC, and RTC.
    • Example: ATxmega128A1, which has 128KB of flash memory, 8KB of SRAM, and 2KB of EEPROM.
  • AT91SAM series: This series of ARM-based microcontrollers combines the low power consumption and high performance of the AVR architecture with the advanced features and processing power of the ARM architecture.
    • Example: AT91SAM9G25, which is based on the ARM926EJ-S core and has 64KB of SRAM, 32KB of ROM, and a variety of peripheral features such as Ethernet and USB.
  • AVR32 series: This series of 32-bit AVR microcontrollers offers high processing power and advanced features such as floating-point processing, DMA, and high-speed connectivity.
    • Example: AVR32 UC3A0512, which has 512KB of flash memory, 64KB of SRAM, and a variety of peripheral features such as Ethernet, USB, and CAN.

Overall, AVR microcontrollers are versatile and widely used in a variety of applications, such as automotive electronics, home automation, industrial automation, robotics, and consumer electronics. They can be programmed using a variety of programming languages and development environments, including C, C++, Assembly, and Arduino.

Comprehensive Atmel Microcontroller Series

AT90 Series:
AT90CAN128	AT90CAN32	AT90CAN64
AT90PWM1	AT90PWM161	AT90PWM2
AT90PWM261	AT90PWM2B	AT90PWM3
AT90PWM316	AT90PWM3B	AT90PWM81
AT90USB1286	AT90USB1287	AT90USB162
AT90USB646	AT90USB647	AT90USB82

ATmega Series:
ATmega128	ATmega1284	ATmega128A
ATmega128x	ATmega16	ATmega1608
ATmega1609	ATmega162	ATmega164
ATmega164P	ATmega165A	ATmega165P
ATmega165PA	ATmega168	ATmega168A
ATmega168P	ATmega168PA	ATmega168PB
ATmega169A	ATmega169P	ATmega169PA
ATmega16A	ATmega16M1	ATmega16U2
ATmega16U4	ATmega256x	ATmega32
ATmega3208	ATmega3209	ATmega324
ATmega324P	ATmega324PB	ATmega325
ATmega3250	ATmega3250A	ATmega3250P
ATmega3250PA	ATmega325A	ATmega325P
ATmega325PA	ATmega328	ATmega328P
ATmega328PB	ATmega329	ATmega3290
ATmega3290A	ATmega3290P	ATmega3290PA
ATmega329A	ATmega329P	ATmega329PA
ATmega32A	ATmega32M1	ATmega32U2
ATmega32U4	ATmega406	ATmega48
ATmega4808	ATmega4809	ATmega48A
ATmega48P	ATmega48PA	ATmega48PB
ATmega48V	ATmega64	ATmega640
ATmega644	ATmega644P	ATmega645
ATmega6450	ATmega6450A	ATmega6450P
ATmega645A	ATmega645P	ATmega649
ATmega6490	ATmega6490A	ATmega6490P
ATmega649A	ATmega649P	ATmega64A
ATmega64M1	ATmega8		ATmega808
ATmega809	ATmega8515	ATmega8535
ATmega88	ATmega88A	ATmega88P
ATmega88PA	ATmega88PB	ATmega8A
ATmega8U2	ATtiny10	ATtiny102

ATtiny Series:
ATtiny104	ATtiny12	ATtiny13
ATtiny13A	ATtiny1604	ATtiny3217
ATtiny1606  	ATtiny3217	ATtiny1607
ATtiny3217	ATtiny1614  	ATtiny3217
ATtiny1616  	ATtiny3217	ATtiny1617
ATtiny3217	ATtiny1634	ATtiny167
ATtiny20	ATtiny202	ATtiny212
ATtiny214	ATtiny2313	ATtiny24
ATtiny25	ATtiny26	ATtiny28L
ATtiny3216	ATtiny3217	ATtiny3217
ATtiny4
ATtiny40	ATtiny402	ATtiny406
ATtiny412	ATtiny414	ATtiny416
ATtiny417	ATtiny43	ATtiny4313
ATtiny44	ATtiny441	ATtiny45
ATtiny48	ATtiny5		ATtiny806
ATtiny807	ATtiny814	ATtiny816
ATtiny817	ATtiny828	ATtiny84
ATtiny841	ATtiny85	ATtiny87
ATtiny88	ATtiny9		ATtinyx04
ATtinyx61	ATtinyx61A	XMEGA A1

XMEGA Series:
XMEGA A1U	XMEGA A3	XMEGA A3B
XMEGA A3BU	XMEGA A3U	XMEGA A4
XMEGA A4U	XMEGA B1	XMEGA B3
XMEGA C3	XMEGA C4	XMEGA D3

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AVR Input Output Port Programming

In AVR microcontroller programming, input/output ports are used to interface with external devices such as sensors, switches, LEDs, motors, and other peripherals. Here’s an example of how to program AVR input/output ports using C language:

#include <avr/io.h>
#include <util/delay.h>

int main(void)
{
    // Set PORTB as output and PORTC as input
    DDRB = 0xFF;
    DDRC = 0x00;

    while(1)
    {
        // Read the value of PINC3
        if(PINC & (1 << PINC3))
        {
            // If PINC3 is high, turn on LED connected to PB0
            PORTB |= (1 << PB0);
        }
        else
        {
            // If PINC3 is low, turn off LED connected to PB0
            PORTB &= ~(1 << PB0);
        }
    }
}

In this example, we set PORTB as an output port by setting all of its pins to output mode. We set PORTC as an input port by setting all of its pins to input mode. Then, we use a while loop to continuously check the value of PINC3. If PINC3 is high, we turn on an LED connected to PB0 by setting the corresponding bit in PORTB to high. If PINC3 is low, we turn off the LED by setting the corresponding bit in PORTB to low.

Note that the & and | operators are used to manipulate individual bits in the port registers. The << operator is used to shift the binary value of 1 to the left by a certain number of bits to set a particular bit high or low. The ~ operator is used to invert the value of a bit. The util/delay.h library is used to create a delay between each loop iteration.

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How to use AT24C32 EEPROM with ATmega328PB in Microchip Studio

AT24C32 is an i2c compatible serial EEPROM which can be programmed using a microcontroller.

The AT24C32 provides 32,768 bits of serial electrically erasable and programmable
read-only memory (EEPROM). The device’s cascadable feature allows up to 8 devices to share a common 2-
wire bus. The device is optimized for use in many industrial and commercial applications
where low power and low voltage operation are essential. The AT24C32/64 is
available in space-saving 8-pin JEDEC PDIP, 8-pin JEDEC SOIC, 8-pin EIAJ SOIC,
and 8-pin TSSOP (AT24C64) packages and is accessed via a 2-wire serial interface.
In addition, the entire family is available in 2.7V (2.7V to 5.5V) and 1.8V (1.8V to 5.5V)
versions.

/*
 * main.c
 *
 * Created: 8/24/2022 10:53:05 PM
 *  Author: abhay
 */ 
#define F_CPU 16000000
#include <xc.h>
#include "util/delay.h"
#include "uart.h"
#include <stdio.h>
#define FALSE 0
#define TRUE 1

void EEOpen();
uint8_t EEWriteByte(uint16_t,uint8_t);
uint8_t EEReadByte(uint16_t address);

int main(void)
{
	UART_Init();
	EEOpen();
	char buff[20];
	sprintf(buff,"Hello EEPROM TEST \nBy: \t ABHAY");
	UART_SendString(buff);
	//Fill whole eeprom 32KB (32768 bytes)
	//with number 7
	uint16_t address;
	char failed;
	failed = 0 ;
	for(address=0;address< (32768);address++)
	{
		sprintf(buff,"address =  %d \n",address);
		UART_SendString(buff);
		if(EEWriteByte(address,5)==0)
		{
			//Write Failed
			sprintf(buff,"write Failed %x \n",address);
			UART_SendString(buff);
			failed = 1;
			break;
		}
	}
	
	if(!failed)
	{
		//We have Done it !!!
		
		sprintf(buff,"Write Success !\n");
		UART_SendString(buff);
	}
    while(1)
    {
        //TODO:: Please write your application code 
		//Check if every location in EEPROM has
		//number 7 stored
		failed=0;
		for(address=0;address < 32768 ; address++)
		{
			if(EEReadByte(address)!=5)
			{
				//Failed !
			
				
				sprintf(buff,"Verify Failed %x \n",address);
				UART_SendString(buff);
				
				failed=1;
				break;
			}
		}

		if(!failed)
		{
			//We have Done it !!!
			
			sprintf(buff,"Write Success !\n");
			UART_SendString(buff);
		}
		
    }
}


void EEOpen()
{
	//Set up TWI Module
	TWBR0 = 5;
	TWSR0 &= (~((1<<TWPS1)|(1<<TWPS0)));

}

uint8_t EEWriteByte(uint16_t address,uint8_t data)
{
	do
	{
		//Put Start Condition on TWI Bus
		TWCR0=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN);

		//Poll Till Done
		while(!(TWCR0 & (1<<TWINT)));

		//Check status
		if((TWSR0 & 0xF8) != 0x08)
			return FALSE;

		//Now write SLA+W
		//EEPROM @ 00h
		TWDR0=0b10100000;	

		//Initiate Transfer
		TWCR0=(1<<TWINT)|(1<<TWEN);

		//Poll Till Done
		while(!(TWCR0 & (1<<TWINT)));
	
	}while((TWSR0 & 0xF8) != 0x18);
		

	//Now write ADDRH
	TWDR0=(address>>8);

	//Initiate Transfer
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x28)
		return FALSE;

	//Now write ADDRL
	TWDR0=(address);

	//Initiate Transfer
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x28)
		return FALSE;

	//Now write DATA
	TWDR0=(data);

	//Initiate Transfer
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x28)
		return FALSE;

	//Put Stop Condition on bus
	TWCR0=(1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
	
	//Wait for STOP to finish
	while(TWCR0 & (1<<TWSTO));

	//Wait untill Writing is complete
	_delay_ms(1);

	//Return TRUE
	return TRUE;

}

uint8_t EEReadByte(uint16_t address)
{
	uint8_t data;

	//Initiate a Dummy Write Sequence to start Random Read
	do
	{
		//Put Start Condition on TWI Bus
		TWCR0=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN);

		//Poll Till Done
		while(!(TWCR0 & (1<<TWINT)));

		//Check status
		if((TWSR0 & 0xF8) != 0x08)
			return FALSE;

		//Now write SLA+W
		//EEPROM @ 00h
		TWDR0=0b10100000;	

		//Initiate Transfer
		TWCR0=(1<<TWINT)|(1<<TWEN);

		//Poll Till Done
		while(!(TWCR0 & (1<<TWINT)));
	
	}while((TWSR0 & 0xF8) != 0x18);
		

	//Now write ADDRH
	TWDR0=(address>>8);

	//Initiate Transfer
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x28)
		return FALSE;

	//Now write ADDRL
	TWDR0=(address);

	//Initiate Transfer
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x28)
		return FALSE;

	//*************************DUMMY WRITE SEQUENCE END **********************


	
	//Put Start Condition on TWI Bus
	TWCR0=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x10)
		return FALSE;

	//Now write SLA+R
	//EEPROM @ 00h
	TWDR0=0b10100001;	

	//Initiate Transfer
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Poll Till Done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x40)
		return FALSE;

	//Now enable Reception of data by clearing TWINT
	TWCR0=(1<<TWINT)|(1<<TWEN);

	//Wait till done
	while(!(TWCR0 & (1<<TWINT)));

	//Check status
	if((TWSR0 & 0xF8) != 0x58)
		return FALSE;

	//Read the data
	data=TWDR0;

	//Put Stop Condition on bus
	TWCR0=(1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
	
	//Wait for STOP to finish
	while(TWCR0 & (1<<TWSTO));

	//Return TRUE
	return data;
}

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How to use DS1307 RTC with ATmega328PB via I2C in Microchip Studio

The DS1307 Real Time Clock uses I2c communication lines to connect with the microcontroller.

I2C uses two lines commonly known as Serial Data/Address or SDA and Serial Clock Line or SCL. The two lines SDA and SCL are standardised and they are implemented using either an open collector or open drain configuration. What this means is that you need to pull these lines UP to VCC. For complete information on how the i2C is implemented in ATmega328PB, you need to go through the section of the datasheet called TWI or Two-Wire Serial Interface.

To start I2C in ATmega328PB, first the SCL frequency needs to set which must be under 100KHz .

To set the SCL frequency you set two registers TWBR0 and TWSR0.

TWSR0 has two bit 0 and bit 1; which sets the prescaler for the clock to the TWI.

Then TWBR0 needs to be set which can anything from 0 to 255.

THen you need to write the I2C functions for start, repeated start, data trasmission and recepetion and stop.

/*
 * main.c
 *
 * Created: 8/20/2022 2:08:09 PM
 *  Author: abhay
 */ 
#define F_CPU 16000000
#include <xc.h>
#include <avr/interrupt.h>

#include <stdio.h>
#include "util/delay.h"
#include "uart.h"


#define Device_Write_address	0xD0				/* Define RTC DS1307 slave address for write operation */
#define Device_Read_address		0xD1				/* Make LSB bit high of slave address for read operation */
#define TimeFormat12			0x40				/* Define 12 hour format */
#define AMPM					0x20

int second,minute,hour,day,date,month,year;

void TWI_init_master(void) // Function to initialize master
{
	TWBR0=127;    // Bit rate
	TWSR0= (1<<TWPS1)|(1<<TWPS0);    // Setting prescalar bits
	// SCL freq= F_CPU/(16+2(TWBR).4^TWPS)
}


								
uint8_t  I2C_Start(char write_address);			/* I2C start function */
uint8_t  I2C_Repeated_Start(char read_address);	/* I2C repeated start function */
void I2C_Stop();								/* I2C stop function */
void I2C_Start_Wait(char write_address);		/* I2C start wait function */
uint8_t  I2C_Write(char data);					/* I2C write function */
int I2C_Read_Ack();							/* I2C read ack function */
int I2C_Read_Nack();							/* I2C read nack function */

void RTC_Read_Clock(char read_clock_address)
{
	I2C_Start(Device_Write_address);				/* Start I2C communication with RTC */
	I2C_Write(read_clock_address);					/* Write address to read */
	I2C_Repeated_Start(Device_Read_address);		/* Repeated start with device read address */

	second = I2C_Read_Ack();						/* Read second */
	minute = I2C_Read_Ack();						/* Read minute */
	hour = I2C_Read_Nack();							/* Read hour with Nack */
	I2C_Stop();										/* Stop i2C communication */
}

void RTC_Read_Calendar(char read_calendar_address)
{
	I2C_Start(Device_Write_address);
	I2C_Write(read_calendar_address);
	I2C_Repeated_Start(Device_Read_address);

	day = I2C_Read_Ack();							/* Read day */
	date = I2C_Read_Ack();							/* Read date */
	month = I2C_Read_Ack();							/* Read month */
	year = I2C_Read_Nack();							/* Read the year with Nack */
	I2C_Stop();										/* Stop i2C communication */
}

int main(void)
{
	char buffer[20];
	const char* days[7]= {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
	UART_Init();
	TWI_init_master();
	sei();
	
	I2C_Start(Device_Write_address);				/* Start I2C communication with RTC */
	I2C_Write(0);					/* Write address to read */
	I2C_Write(0x00);	//sec
	I2C_Write(0x00);	//min			/* Write address to read */
	I2C_Write(0x17);	//hour
	I2C_Write(0x03);	//tuesday
	I2C_Write(0x23);	//day
	I2C_Write(0x09);	//month
	I2C_Write(0x21);	//year
	I2C_Stop();										/* Stop i2C communication */
	

 

    
	while(1)
    {
        //TODO:: Please write your application code 
		RTC_Read_Clock(0);
		//UART_Transmit(second);
		sprintf(buffer, "\n%02x:%02x:%02x  ", (hour & 0b00011111), minute, second);
		UART_SendString(buffer);
		RTC_Read_Calendar(3);
		sprintf(buffer, "%02x/%02x/%02x %s", date, month, year,days[day-1]);
		UART_SendString(buffer);
		_delay_ms(1000);
    }
}

uint8_t I2C_Start(char write_address)						/* I2C start function */
{
	uint8_t status;											/* Declare variable */
	TWCR0 = (1<<TWSTA)|(1<<TWEN)|(1<<TWINT);					/* Enable TWI, generate start condition and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (start condition) */
	status = TWSR0 & 0xF8;									/* Read TWI status register with masking lower three bits */
	if (status != 0x08)										/* Check weather start condition transmitted successfully or not? */
	return 0;												/* If not then return 0 to indicate start condition fail */
	TWDR0 = write_address;									/* If yes then write SLA+W in TWI data register */
	TWCR0 = (1<<TWEN)|(1<<TWINT);							/* Enable TWI and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (Write operation) */
	status = TWSR0 & 0xF8;									/* Read TWI status register with masking lower three bits */
	if (status == 0x18)										/* Check weather SLA+W transmitted & ack received or not? */
	return 1;												/* If yes then return 1 to indicate ack received i.e. ready to accept data byte */
	if (status == 0x20)										/* Check weather SLA+W transmitted & nack received or not? */
	return 2;												/* If yes then return 2 to indicate nack received i.e. device is busy */
	else
	return 3;												/* Else return 3 to indicate SLA+W failed */
}

uint8_t I2C_Repeated_Start(char read_address)				/* I2C repeated start function */
{
	uint8_t status;											/* Declare variable */
	TWCR0 = (1<<TWSTA)|(1<<TWEN)|(1<<TWINT);					/* Enable TWI, generate start condition and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (start condition) */
	status = TWSR0 & 0xF8;									/* Read TWI status register with masking lower three bits */
	if (status != 0x10)										/* Check weather repeated start condition transmitted successfully or not? */
	return 0;												/* If no then return 0 to indicate repeated start condition fail */
	TWDR0 = read_address;									/* If yes then write SLA+R in TWI data register */
	TWCR0 = (1<<TWEN)|(1<<TWINT);							/* Enable TWI and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (Write operation) */
	status = TWSR0 & 0xF8;									/* Read TWI status register with masking lower three bits */
	if (status == 0x40)										/* Check weather SLA+R transmitted & ack received or not? */
	return 1;												/* If yes then return 1 to indicate ack received */
	if (status == 0x20)										/* Check weather SLA+R transmitted & nack received or not? */
	return 2;												/* If yes then return 2 to indicate nack received i.e. device is busy */
	else
	return 3;												/* Else return 3 to indicate SLA+W failed */
}

void I2C_Stop()												/* I2C stop function */
{
	TWCR0=(1<<TWSTO)|(1<<TWINT)|(1<<TWEN);					/* Enable TWI, generate stop condition and clear interrupt flag */
	while(TWCR0 & (1<<TWSTO));								/* Wait until stop condition execution */
}

void I2C_Start_Wait(char write_address)						/* I2C start wait function */
{
	uint8_t status;											/* Declare variable */
	while (1)
	{
		TWCR0 = (1<<TWSTA)|(1<<TWEN)|(1<<TWINT);				/* Enable TWI, generate start condition and clear interrupt flag */
		while (!(TWCR0 & (1<<TWINT)));						/* Wait until TWI finish its current job (start condition) */
		status = TWSR0 & 0xF8;								/* Read TWI status register with masking lower three bits */
		if (status != 0x08)									/* Check weather start condition transmitted successfully or not? */
		continue;											/* If no then continue with start loop again */
		TWDR0 = write_address;								/* If yes then write SLA+W in TWI data register */
		TWCR0 = (1<<TWEN)|(1<<TWINT);						/* Enable TWI and clear interrupt flag */
		while (!(TWCR0 & (1<<TWINT)));						/* Wait until TWI finish its current job (Write operation) */
		status = TWSR0 & 0xF8;								/* Read TWI status register with masking lower three bits */
		if (status != 0x18 )								/* Check weather SLA+W transmitted & ack received or not? */
		{
			I2C_Stop();										/* If not then generate stop condition */
			continue;										/* continue with start loop again */
		}
		break;												/* If yes then break loop */
	}
}

uint8_t I2C_Write(char data)								/* I2C write function */
{
	uint8_t status;											/* Declare variable */
	TWDR0 = data;											/* Copy data in TWI data register */
	TWCR0 = (1<<TWEN)|(1<<TWINT);							/* Enable TWI and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (Write operation) */
	status = TWSR0 & 0xF8;									/* Read TWI status register with masking lower three bits */
	if (status == 0x28)										/* Check weather data transmitted & ack received or not? */
	return 0;												/* If yes then return 0 to indicate ack received */
	if (status == 0x30)										/* Check weather data transmitted & nack received or not? */
	return 1;												/* If yes then return 1 to indicate nack received */
	else
	return 2;												/* Else return 2 to indicate data transmission failed */
}

int I2C_Read_Ack()											/* I2C read ack function */
{
	TWCR0=(1<<TWEN)|(1<<TWINT)|(1<<TWEA);					/* Enable TWI, generation of ack and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (read operation) */
	return TWDR0;											/* Return received data */
}

int I2C_Read_Nack()										/* I2C read nack function */
{
	TWCR0=(1<<TWEN)|(1<<TWINT);								/* Enable TWI and clear interrupt flag */
	while (!(TWCR0 & (1<<TWINT)));							/* Wait until TWI finish its current job (read operation) */
	return TWDR0;											/* Return received data */
}
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How to use UART Receive complete ISR of ATmega328PB using microchip studio

When you enable the communication using the UART. You have the flexibility to either use the Polling or Interrupt method to continue with your programming.

Polling halts the execution of the program and waits for the UART peripheral to receive something so that program execution must continue. But it eats a lot of the computing time.

So, Interrupt Service Routine is written and implemented such the program execution does not stop. It will stop when there is an interrupt and when there is data in the UDR0 register of UART. Then the ISR will execute and then transfer the control to the main program. Which saves a lot of computing time.

you have to add an interrupt library in your program.

#include <avr/interrupt.h>

Then you need to enable the Global interrupt flag.

.
.
.
int main()
{
.
.
.
sei();            // This is Set Enable Interryupt

   while(1)
  {
     // This is your application code.
   }

}

Then you need to enable the UART receive complete interrupt. by setting ‘1’ to RXCIE0 bit of USCR0B register.

Write the ISR function which takes “USART0_RX_vect” as the argument.

char Received_char;
ISR(USART0_RX_vect)
{
	Received_char = UDR0;
}

int main()
{
UCSR0B = (1 << RXCIE0)|(1<<RXEN0)|(1<<TXEN0); 
.
.
.
sei();
while(1);
{
}

}

The above code shows you how to implement UART receive complete ISR. It is not a full initialisation code. You still have to write the UBRR and the frame control to enable the uart peripheral.