?? uart.c
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#include <stdio.h>#include <avr/io.h>#include <avr/sfr_defs.h>#include "uart.h"/* some mcus have multiple uarts */#ifdef UDR0#define UBRRH UBRR0H#define UBRRL UBRR0L#define UDR UDR0#define UCSRA UCSR0A#define UDRE UDRE0#define RXC RXC0#define UCSRB UCSR0B#define RXEN RXEN0#define TXEN TXEN0#define UCSRC UCSR0C#define URSEL #define UCSZ0 UCSZ00#define UCSZ1 UCSZ01#define UCSRC_SELECT 0#else#define UCSRC_SELECT (1 << URSEL)#endif#define BAUD 9600UL#define UBRRVAL (F_CPU/(BAUD*16)-1)static int _uart_putc(char c, FILE* stream);static int _uart_getc(FILE* stream);static FILE stdio = FDEV_SETUP_STREAM(_uart_putc, _uart_getc, _FDEV_SETUP_RW);void uart_init(){ /* set baud rate */ UBRRH = UBRRVAL >> 8; UBRRL = UBRRVAL & 0xff; /* set frame format: 8 bit, no parity, 1 bit */ UCSRC = UCSRC_SELECT | (1 << UCSZ1) | (1 << UCSZ0); /* enable serial receiver and transmitter */ UCSRB = (1 << RXEN) | (1 << TXEN);}void uart_connect_stdio(){ stdin = stdout = stderr = &stdio;}void uart_putc(uint8_t c){ if(c == '\n') uart_putc('\r'); /* wait until transmit buffer is empty */ loop_until_bit_is_set(UCSRA, UDRE); /* send next byte */ UDR = c;}int _uart_putc(char c, FILE* stream){ uart_putc(c); return 0;}void uart_putc_hex(uint8_t b){ /* upper nibble */ if((b >> 4) < 0x0a) uart_putc((b >> 4) + '0'); else uart_putc((b >> 4) - 0x0a + 'a'); /* lower nibble */ if((b & 0x0f) < 0x0a) uart_putc((b & 0x0f) + '0'); else uart_putc((b & 0x0f) - 0x0a + 'a');}uint8_t uart_getc(){ /* wait until receive buffer is full */ loop_until_bit_is_set(UCSRA, RXC); uint8_t b = UDR; if(b == '\r') b = '\n'; return b;}int _uart_getc(FILE* stream){ return uart_getc();}?? 快捷鍵說明
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