UART.rar_UART AVR_in

/********************************************* * Chip type : ATmega8 * Clock frequency : 4,000000 MHz *********************************************/ #include <ctype.h> #include <stdint.h> #include <stdio.h> #include <avr/io.h> #include <avr/pgmspace.h> #include <avr/interrupt.h> #include <inttypes.h> #define F_OSC 4000000 /* oscillator-frequency in Hz */ #define UART_BAUD_RATE 9600 #define UART_BAUD_CALC(UART_BAUD_RATE,F_OSC) ((F_OSC)/((UART_BAUD_RATE)*16l)-1) void delay_ms(unsigned short ms) { unsigned short outer1, outer2; outer1 = 200; while (outer1) { outer2 = 1000; while (outer2) { while ( ms ) ms--; outer2--; } outer1--; } } void usart_putc(unsigned char c) { // wait until UDR ready while(!(UCSRA & (1 << UDRE))); UDR = c; // send character } void uart_puts (char *s) { // loop until *s != NULL while (*s) { usart_putc(*s); s++; } } void init(void) { // set baud rate UBRRH = (uint8_t)(UART_BAUD_CALC(UART_BAUD_RATE,F_OSC)>>8); UBRRL = (uint8_t)UART_BAUD_CALC(UART_BAUD_RATE,F_OSC); // Enable receiver and transmitter; enable RX interrupt UCSRB = (1 << RXEN) | (1 << TXEN) | (1 << RXCIE); //asynchronous 8N1 UCSRC = (1 << URSEL) | (3 << UCSZ0); } // INTERRUPT can be interrupted // SIGNAL can't be interrupted int main(void) { init(); // init USART while (1) { uart_puts("1234"); } return 0; }