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uart: port to STM32F4

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King Kévin 2020-11-27 16:49:59 +01:00
parent aae4009fbe
commit 2249f460e3
1 changed files with 16 additions and 12 deletions
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28
lib/uart.c
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@ -8,7 +8,6 @@
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdio.h> // standard I/O facilities
#include <stdlib.h> // general utilities
/* STM32 (including CM3) libraries */
@ -25,9 +24,12 @@
* @{
*/
#define UART_ID 1 /**< USART peripheral */
#define UART_TX PA9 /**< pin used for USART TX */
#define UART_RX PA10 /**< pin used for USART RX */
#define UART_AF GPIO_AF7 /**< alternate function for UART pins */
/** @} */
#define UART_BAUDRATE 921600 /**< serial baud rate, in bits per second (with 8N1 8 bits, no parity bit, 1 stop bit settings) */
#define UART_BAUDRATE 115200 /**< serial baud rate, in bits per second (with 8N1 8 bits, no parity bit, 1 stop bit settings) */
/* output ring buffer, indexes, and available memory */
static volatile uint8_t tx_buffer[128] = {0}; /**< ring buffer for data to transmit (size must be a power of 2) */
@ -36,16 +38,18 @@ static volatile uint16_t tx_used = 0; /**< how much data needs to be transmitted
void uart_setup(void)
{
/* enable UART I/O peripheral */
rcc_periph_clock_enable(RCC_USART_PORT(UART_ID)); // enable clock for UART port peripheral
rcc_periph_clock_enable(RCC_USART(UART_ID)); // enable clock for UART peripheral
rcc_periph_reset_pulse(RST_USART(UART_ID)); // reset peripheral
rcc_periph_clock_enable(RCC_AFIO); // enable pin alternate function (UART)
gpio_set_mode(USART_TX_PORT(UART_ID), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, USART_TX_PIN(UART_ID)); // setup GPIO pin UART transmit
gpio_set_mode(USART_RX_PORT(UART_ID), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, USART_RX_PIN(UART_ID)); // setup GPIO pin UART receive
gpio_set(USART_RX_PORT(UART_ID), USART_RX_PIN(UART_ID)); // pull up to avoid noise when not connected
// configure pins
rcc_periph_clock_enable(GPIO_RCC(UART_TX)); // enable clock for USART TX pin port peripheral
gpio_mode_setup(GPIO_PORT(UART_TX), GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN(UART_TX)); // set TX pin to alternate function
gpio_set_output_options(GPIO_PORT(UART_TX), GPIO_OTYPE_PP, GPIO_OSPEED_25MHZ, GPIO_PIN(UART_TX)); // set TX pin output as push-pull
gpio_set_af(GPIO_PORT(UART_TX), UART_AF, GPIO_PIN(UART_TX)); // set alternate function to USART
rcc_periph_clock_enable(GPIO_RCC(UART_RX)); // enable clock for USART RX pin port peripheral
gpio_mode_setup(GPIO_PORT(UART_RX), GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN(UART_RX)); // set GPIO to alternate function, with pull up to avoid noise in case it is not connected
gpio_set_af(GPIO_PORT(UART_RX), UART_AF, GPIO_PIN(UART_RX)); // set alternate function to USART
/* setup UART parameters */
// configure USART
rcc_periph_clock_enable(RCC_USART(UART_ID)); // enable clock for USART peripheral
rcc_periph_reset_pulse(RST_USART(UART_ID)); // reset peripheral
usart_set_baudrate(USART(UART_ID), UART_BAUDRATE);
usart_set_databits(USART(UART_ID), 8);
usart_set_stopbits(USART(UART_ID), USART_STOPBITS_1);
@ -57,7 +61,7 @@ void uart_setup(void)
usart_enable_rx_interrupt(USART(UART_ID)); // enable receive interrupt
usart_enable(USART(UART_ID)); // enable UART
/* reset buffer states */
// reset buffer states
tx_i = 0;
tx_used = 0;
}