cpu/stm32f1: reworked UART implementation

This commit is contained in:
Hauke Petersen 2016-03-16 10:27:43 +01:00
parent 91904a469c
commit dff203e7dd
2 changed files with 82 additions and 105 deletions

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@ -125,6 +125,18 @@ typedef struct {
uint8_t irqn; /**< global IRQ channel */ uint8_t irqn; /**< global IRQ channel */
} timer_conf_t; } timer_conf_t;
/**
* @brief UART configuration options
*/
typedef struct {
USART_TypeDef *dev; /**< UART device */
gpio_t rx_pin; /**< TX pin */
gpio_t tx_pin; /**< RX pin */
uint32_t rcc_pin; /**< bit in the RCC register */
uint8_t bus; /**< peripheral bus */
uint8_t irqn; /**< interrupt number */
} uart_conf_t;
/** /**
* @brief Configure the alternate function for the given pin * @brief Configure the alternate function for the given pin
* *

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@ -1,9 +1,9 @@
/* /*
* Copyright (C) 2014 Freie Universität Berlin * Copyright (C) 2014-2016 Freie Universität Berlin
* *
* This file is subject to the terms and conditions of the GNU Lesser General * This file is subject to the terms and conditions of the GNU Lesser
* Public License v2.1. See the file LICENSE in the top level directory for more * General Public License v2.1. See the file LICENSE in the top level
* details. * directory for more details.
*/ */
/** /**
@ -33,142 +33,107 @@
/** /**
* @brief Allocate memory to store the callback functions. * @brief Allocate memory to store the callback functions.
*/ */
static uart_isr_ctx_t config[UART_NUMOF]; static uart_isr_ctx_t isr_ctx[UART_NUMOF];
static int init_base(uart_t uart, uint32_t baudrate); static inline USART_TypeDef *dev(uart_t uart)
{
return uart_config[uart].dev;
}
static void clk_en(uart_t uart)
{
if (uart_config[uart].bus == APB1) {
RCC->APB1ENR |= uart_config[uart].rcc_pin;
}
else {
RCC->APB2ENR |= uart_config[uart].rcc_pin;
}
}
int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg) int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
{ {
int res; uint32_t bus_clk;
/* initialize UART in blocking mode first */
res = init_base(uart, baudrate);
if (res < 0) {
return res;
}
/* enable global interrupt and configure the interrupts priority */
switch (uart) {
#if UART_0_EN
case UART_0:
NVIC_EnableIRQ(UART_0_IRQ);
UART_0_DEV->CR1 |= USART_CR1_RXNEIE;
break;
#endif
#if UART_1_EN
case UART_1:
NVIC_EnableIRQ(UART_1_IRQ);
UART_1_DEV->CR1 |= USART_CR1_RXNEIE;
break;
#endif
default:
return -2;
}
/* register callbacks */
config[uart].rx_cb = rx_cb;
config[uart].arg = arg;
return 0;
}
static int init_base(uart_t uart, uint32_t baudrate)
{
USART_TypeDef *dev;
uint32_t bus_freq;
gpio_t rx_pin, tx_pin;
uint16_t mantissa; uint16_t mantissa;
uint8_t fraction; uint8_t fraction;
/* enable UART and port clocks and select devices */ /* make sure the given device is valid */
switch (uart) { if (uart >= UART_NUMOF) {
#if UART_0_EN return -1;
case UART_0:
dev = UART_0_DEV;
rx_pin = UART_0_RX_PIN;
tx_pin = UART_0_TX_PIN;
bus_freq = UART_0_BUS_FREQ;
/* enable clocks */
UART_0_CLKEN();
break;
#endif
#if UART_1_EN
case UART_1:
dev = UART_1_DEV;
tx_pin = UART_1_TX_PIN;
rx_pin = UART_1_RX_PIN;
bus_freq = UART_1_BUS_FREQ;
/* enable clocks */
UART_1_CLKEN();
break;
#endif
default:
return -2;
} }
/* save ISR context */
isr_ctx[uart].rx_cb = rx_cb;
isr_ctx[uart].arg = arg;
/* configure RX and TX pin */ /* configure RX and TX pin */
gpio_init_af(tx_pin, GPIO_AF_OUT_PP); gpio_init(uart_config[uart].rx_pin, GPIO_DIR_IN, GPIO_NOPULL);
gpio_init(rx_pin, GPIO_DIR_IN, GPIO_NOPULL); gpio_init_af(uart_config[uart].tx_pin, GPIO_AF_OUT_PP);
/* configure UART to mode 8N1 with given baudrate */ /* enable the clock */
bus_freq /= baudrate; clk_en(uart);
mantissa = (uint16_t)(bus_freq / 16);
fraction = (uint8_t)(bus_freq - (mantissa * 16)); /* reset UART configuration -> defaults to 8N1 mode */
dev->BRR = 0; dev(uart)->CR1 = 0;
dev->BRR |= ((mantissa & 0x0fff) << 4) | (0x0f & fraction); dev(uart)->CR2 = 0;
dev(uart)->CR3 = 0;
/* calculate and apply baudrate */
bus_clk = (uart_config[uart].bus == APB1) ? CLOCK_APB1 : CLOCK_APB2;
bus_clk /= baudrate;
mantissa = (uint16_t)(bus_clk / 16);
fraction = (uint8_t)(bus_clk - (mantissa * 16));
dev(uart)->BRR = ((mantissa & 0x0fff) << 4) | (fraction & 0x0f);
/* enable the UART's global interrupt and activate it */
NVIC_EnableIRQ(uart_config[uart].irqn);
dev(uart)->CR1 = (USART_CR1_UE | USART_CR1_TE |
USART_CR1_RE | USART_CR1_RXNEIE);
/* enable receive and transmit mode */
dev->CR1 |= USART_CR1_UE | USART_CR1_TE | USART_CR1_RE;
return 0; return 0;
} }
void uart_write(uart_t uart, const uint8_t *data, size_t len) void uart_write(uart_t uart, const uint8_t *data, size_t len)
{ {
USART_TypeDef *dev;
switch (uart) {
#if UART_0_EN
case UART_0:
dev = UART_0_DEV;
break;
#endif
#if UART_1_EN
case UART_1:
dev = UART_1_DEV;
break;
#endif
}
for (size_t i = 0; i < len; i++) { for (size_t i = 0; i < len; i++) {
while (!(dev->SR & USART_SR_TXE)) {} while(!(dev(uart)->SR & USART_SR_TXE)) {}
dev->DR = data[i]; dev(uart)->DR = data[i];
} }
} }
static inline void irq_handler(uart_t uartnum, USART_TypeDef *dev) static inline void irq_handler(uart_t uart)
{ {
if (dev->SR & USART_SR_RXNE) { uint32_t status = dev(uart)->SR;
uint8_t data = (uint8_t)dev->DR;
config[uartnum].rx_cb(config[uartnum].arg, data); if (status & USART_SR_RXNE) {
char data = (char)dev(uart)->DR;
isr_ctx[uart].rx_cb(isr_ctx[uart].arg, data);
} }
else if (dev->SR & USART_SR_ORE) { if (status & USART_SR_ORE) {
/* ORE is cleared by reading SR and DR sequentially */ /* ORE is cleared by reading SR and DR sequentially */
dev->DR; dev(uart)->DR;
} }
if (sched_context_switch_request) { if (sched_context_switch_request) {
thread_yield(); thread_yield();
} }
} }
#if UART_0_EN #ifdef UART_0_ISR
void UART_0_ISR(void) void UART_0_ISR(void)
{ {
irq_handler(UART_0, UART_0_DEV); irq_handler(0);
} }
#endif #endif
#if UART_1_EN #ifdef UART_1_ISR
void UART_1_ISR(void) void UART_1_ISR(void)
{ {
irq_handler(UART_1, UART_1_DEV); irq_handler(1);
}
#endif
#ifdef UART_2_ISR
void UART_2_ISR(void)
{
irq_handler(2);
} }
#endif #endif