cm3-bluepill/uart.c
2025-07-16 18:00:08 +02:00

38 lines
1.1 KiB
C

#include "uart.h"
#include <errno.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/usart.h>
#include <stdio.h>
#include <unistd.h>
int _write(int file, char *ptr, int len);
void usart_setup(void) {
/* Setup GPIO pin GPIO_USART1_RE_TX on GPIO port B for transmit. */
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;
}