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#include "project.h"
#define BUFFER_SIZE 256
#define USART1_TX GPIO_USART1_TX
#define USART1_TX_PORT GPIOA
#define USART1_RX GPIO_USART1_RX
#define USART1_RX_PORT GPIOA
ring_t rx1_ring;
static uint8_t rx1_ring_buf[BUFFER_SIZE];
ring_t tx1_ring;
static uint8_t tx1_ring_buf[BUFFER_SIZE];
void
usart1_isr (void)
{
uint8_t data;
/* Check if we were called because of RXNE. */
if (((USART_CR1 (USART1) & USART_CR1_RXNEIE) != 0) &&
((USART_SR (USART1) & USART_SR_RXNE) != 0)) {
/* Retrieve the data from the peripheral. */
data = usart_recv (USART1);
ring_write_byte (&rx1_ring, data);
}
/* Check if we were called because of TXE. */
if (((USART_CR1 (USART1) & USART_CR1_TXEIE) != 0) &&
((USART_SR (USART1) & USART_SR_TXE) != 0)) {
if (ring_read_byte (&tx1_ring, &data)) {
/*No more data, Disable the TXE interrupt, it's no longer needed. */
USART_CR1 (USART1) &= ~USART_CR1_TXEIE;
} else
usart_send (USART1, data);
}
}
int
_write (int file, char *ptr, int len)
{
int ret;
if (file == 1) {
ret = len;
usart1_drain();
while (len--) {
if (*ptr == '\n')
ring_write_byte (&tx1_ring, '\r');
ring_write_byte (&tx1_ring, * (ptr++));
}
USART_CR1 (USART1) |= USART_CR1_TXEIE;
return ret;
}
errno = EIO;
return -1;
}
void
usart1_queue (uint8_t d)
{
ring_write_byte (&tx1_ring, d);
USART_CR1 (USART1) |= USART_CR1_TXEIE;
}
void
usart1_drain (void)
{
while (!ring_empty (&tx1_ring));
}
void
usart_init (void)
{
rcc_periph_clock_enable (RCC_USART1);
ring_init (&rx1_ring, rx1_ring_buf, sizeof (rx1_ring_buf));
ring_init (&tx1_ring, tx1_ring_buf, sizeof (tx1_ring_buf));
/* Enable the USART1,2 interrupt. */
nvic_enable_irq (NVIC_USART1_IRQ);
/* Map pins, and usart1 to have pull ups */
MAP_AF_PP (USART1_TX);
MAP_INPUT_PU (USART1_RX);
/* Setup UART1 parameters. */
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_RX);
/* Enable USART1 Receive interrupt. */
USART_CR1 (USART1) |= USART_CR1_RXNEIE;
/* Finally enable the USARTs. */
usart_enable (USART1);
}
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