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/*
Program : kuttyPy.c
author : Ajith Kumar (bpajith@gmail.com)
License : GNU GPL version 3 or above
A program to read/write the microcontroller registers from Python running on PC
*/
#include <avr/io.h>
#define VERSION 99
#define GETVER 1
#define READB 2
#define WRITEB 3
int main (void)
{
uint8_t cmd, data, *port;
// Initialize the RS232 communication link to the PC 38400, 8, 1, N
UCSRB = (1 << RXEN) | (1 << TXEN);
UBRRH = 0;
UBRRL = 12; // At 8MHz clock (12 =>38400 baudrate)
UCSRC = (1 <<URSEL) | (1 << UCSZ1) | (1 << UCSZ0); // 8,1,N
for(;;) // Infinite loop waiting for commands from PC
{
while ( !(UCSRA & (1<<RXC)) ) ; // wait for command from PC
cmd = UDR; // Store the received byte
if(cmd == GETVER)
{
UDR = VERSION;
}
else if(cmd == READB)
{
while ( !(UCSRA & (1<<RXC)) ) ; // wait
port = UDR; // get the port address
UDR = *port;
}
else if(cmd == WRITEB)
{
while ( !(UCSRA & (1<<RXC)) ) ; // wait
port = UDR; // get the register address
while ( !(UCSRA & (1<<RXC)) ) ; // wait
data = UDR; // get the data
*port = data; // write data to the port address
}
// Invalid commands are ignored silently
}
}
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