cm3-bluepill/uart.c
2025-07-16 19:33:35 +02:00

71 lines
1.6 KiB
C

#include "uart.h"
#include <errno.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/usart.h>
#include <sys/stat.h>
#include <unistd.h>
int _write(int file, char *ptr, int len);
int _close(int file);
int _fstat(int file, struct stat *st);
int _isatty(int file);
int _lseek(int file, int ptr, int dir);
int _read(int file, char *ptr, int len);
void usart_setup(void) {
gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
usart_set_baudrate(USART1, 115200);
usart_set_databits(USART1, 8);
usart_set_stopbits(USART1, USART_STOPBITS_1);
usart_set_parity(USART1, USART_PARITY_NONE);
usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
usart_set_mode(USART1, USART_MODE_TX);
usart_enable(USART1);
}
int _write(int file, char *ptr, int len) {
if (file == STDOUT_FILENO || file == STDERR_FILENO) {
for (int i = 0; i < len; i++) {
if (ptr[i] == '\n') {
usart_send_blocking(USART1, '\r');
}
usart_send_blocking(USART1, ptr[i]);
}
return len;
}
errno = EIO;
return -1;
}
int _close(int file) {
(void)file;
return -1;
}
int _fstat(int file, struct stat *st) {
(void)file;
st->st_mode = S_IFCHR;
return 0;
}
int _isatty(int file) {
(void)file;
return 1;
}
int _lseek(int file, int ptr, int dir) {
(void)file;
(void)ptr;
(void)dir;
return 0;
}
// Optional — stubbed read (e.g. for scanf), returns 0 bytes
int _read(int file, char *ptr, int len) {
(void)file;
(void)ptr;
(void)len;
return 0;
}