STM32_Usart.rar_stm32 串口_stm32串口_stm32串口通讯_stm32串口项目

/*************************************************************************** * Atmel AVR USART Library for GCC * Version: 1.0 * * Works with AVR MCUs equiped with USART hardware (ATmega series). * Does not work with older UART's or USI of ATtiny series. * Tested with ATmega8. * * Uses USART Receive Complete Interrupt. Disabling Global Interrupts * after usart initialization disables data receive. * * Jaakko Ala-Paavola 2003/06/28 * http://www.iki.fi/jap email:[email protected] */ #include <avr/io.h> #include <avr/signal.h> #include <avr/interrupt.h> #include <string.h> #include "usart.h" char usart_buffer[USART_BUFFER_SIZE]; volatile unsigned char usart_buffer_pos_first = 0, usart_buffer_pos_last = 0; volatile unsigned char usart_buffer_overflow = 0; void usart_init(unsigned char baud_divider) { // Baud rate selection UBRRH = 0x00; UBRRL = baud_divider; // USART setup UCSRA = 0x02; // 0000 0010 // U2X enabled UCSRC = 0x86; // 1000 0110 // Access UCSRC, Asyncronous 8N1 UCSRB = 0x98; // 1001 1000 // Receiver enabled, Transmitter enabled // RX Complete interrupt enabled sei(); // Enable interrupts globally } void usart_putc(char data) { while (!(UCSRA & 0x20)); // Wait untill USART data register is empty // Transmit data UDR = data; } void usart_puts(char *data) { int len, count; len = strlen(data); for (count = 0; count < len; count++) usart_putc(*(data+count)); } char usart_getc(void) { // Wait untill unread data in ring buffer if (!usart_buffer_overflow) while(usart_buffer_pos_first == usart_buffer_pos_last); usart_buffer_overflow = 0; // Increase first pointer if (++usart_buffer_pos_first >= USART_BUFFER_SIZE) usart_buffer_pos_first = 0; // Get data from the buffer return usart_buffer[usart_buffer_pos_first]; } unsigned char usart_unread_data(void) { if (usart_buffer_overflow) return USART_BUFFER_SIZE; if (usart_buffer_pos_last > usart_buffer_pos_first) return usart_buffer_pos_last - usart_buffer_pos_first; if (usart_buffer_pos_last < usart_buffer_pos_first) return USART_BUFFER_SIZE-usart_buffer_pos_first + usart_buffer_pos_last; return 0; } SIGNAL(SIG_UART_RECV) { // Increase last buffer if (++usart_buffer_pos_last >= USART_BUFFER_SIZE) usart_buffer_pos_last = 0; if (usart_buffer_pos_first == usart_buffer_pos_last) usart_buffer_overflow++; // Put data to the buffer usart_buffer[usart_buffer_pos_last] = UDR; }