From 259ee0e7022ce15f4f2c8294a4fc3de7005d7fab Mon Sep 17 00:00:00 2001 From: fishsoupisgood Date: Mon, 29 Apr 2019 07:30:28 +0100 Subject: working with one set of stripes --- app/usart.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 app/usart.c (limited to 'app/usart.c') diff --git a/app/usart.c b/app/usart.c new file mode 100644 index 0000000..4ba8da2 --- /dev/null +++ b/app/usart.c @@ -0,0 +1,87 @@ +#include "project.h" + +#define BUFFER_SIZE 512 + +ring_t usart_rx_ring; +static uint8_t usart_rx_ring_buf[BUFFER_SIZE]; + +ring_t usart_tx_ring; +static uint8_t usart_tx_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 (&usart_rx_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 (&usart_tx_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); + } +} + +void usart_kick (void) +{ + if (!ring_empty (&usart_tx_ring)) + USART_CR1 (USART1) |= USART_CR1_TXEIE; +} + + +int +_write (int file, char *ptr, int len) +{ + int ret; + + if (file == 1) { + ret = ring_write (&usart_tx_ring, (uint8_t *) ptr, len); + usart_kick(); + + if (ret < 0) + ret = -ret; + + return ret; + } + + errno = EIO; + return -1; +} + + + + +void +usart_init (void) +{ + ring_init (&usart_rx_ring, usart_rx_ring_buf, sizeof (usart_rx_ring_buf)); + ring_init (&usart_tx_ring, usart_tx_ring_buf, sizeof (usart_tx_ring_buf)); + /* Enable the USART1 interrupt. */ + nvic_enable_irq (NVIC_USART1_IRQ); + /* Map pins */ + gpio_set_mode (GPIOA, GPIO_MODE_OUTPUT_50_MHZ, + GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX); + gpio_set_mode (GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, + GPIO_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 USART1. */ + usart_enable (USART1); +} -- cgit v1.2.3