134 lines
2.7 KiB
C
134 lines
2.7 KiB
C
#include "stm32f030x6.h"
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#include <dmx.h>
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#include <stdint.h>
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#include <stm32f0xx.h>
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#include <stdbool.h>
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#include <stm-periph/stm32-gpio-macros.h>
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static GPIO_TypeDef *dmx_tx_port;
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static uint8_t dmx_tx_pin;
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static uint32_t dmx_universe_length;
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static uint8_t *dmx_data_ptr;
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static uint16_t dmx_tx_break_len;
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static uint16_t dmx_tx_break_pause;
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enum dmx_tx_state {
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DMX_TX_OFF,
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DMX_TX_IDLE,
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DMX_TX_BREAK,
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DMX_TX_BREAK_PAUSE,
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DMX_TX_NULLBYTE,
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DMX_TX_DATA,
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};
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static volatile enum dmx_tx_state tx_state;
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/* USART1 TX is mapped on DMA Channel2 */
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static void dmx_break(bool break_enable)
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{
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uint32_t tmp;
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/* Force pin to low */
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dmx_tx_port->BSRR |= (1 << (dmx_tx_pin + 16));
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/* Change pin mode from alternate function (UART) to output and vice versa */
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tmp = dmx_tx_port->MODER;
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if (break_enable) {
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tmp &= MODER_DELETE(dmx_tx_pin);
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tmp |= OUTPUT(dmx_tx_pin);
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} else {
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tmp &= MODER_DELETE(dmx_tx_pin);
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tmp |= ALTFUNC(dmx_tx_pin);
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}
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dmx_tx_port->MODER = tmp;
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}
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void dmx_init(uint8_t *data, uint32_t universe_length, GPIO_TypeDef *tx_port, uint8_t tx_pin,
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uint16_t dmx_delay, uint16_t dmx_break_len, uint16_t break_pause)
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{
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dmx_tx_pin = tx_pin;
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dmx_tx_port = tx_port;
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dmx_data_ptr = data;
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dmx_tx_break_len = dmx_break_len;
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dmx_tx_break_pause = break_pause;
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/* Enable UART1 and TIM14 clock */
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RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
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RCC->APB1ENR |= RCC_APB1ENR_TIM14EN;
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/* Enable DMA clock */
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RCC->AHBENR |= RCC_AHBENR_DMAEN;
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/* Set baudrate: 48MHz / 250k = 129 */
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USART1->BRR = 192u;
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/* Two stop bits */
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USART1->CR2 = USART_CR2_STOP_1;
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/* Transmitter enable, USART enable */
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USART1->CR1 = USART_CR1_TE | USART_CR1_UE;
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/* Configure TIM14 to count in 10 us steps */
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TIM14->PSC = 480u;
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/* Configure the reload value. Must be higher or equal to 200 */
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if (dmx_delay < 2000)
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dmx_delay = 2000;
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TIM14->ARR = dmx_delay - 1;
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/* Enable TIM14 interrupt on update */
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TIM14->DIER = TIM_DIER_UIE | TIM_DIER_CC1IE;
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NVIC_EnableIRQ(TIM14_IRQn);
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}
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void dmx_stream_start(void)
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{
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tx_state = DMX_TX_IDLE;
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TIM14->CR1 |= TIM_CR1_CEN;
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}
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void dmx_stream_stop(void)
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{
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tx_state = DMX_TX_OFF;
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TIM14->CR1 &= ~TIM_CR1_CEN;
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DMA1_Channel2->CCR = 0ul;
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__DSB();
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USART1->CR3 = 0ul;
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}
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void TIM14_IRQHandler(void)
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{
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/* Clear interrupt sources */
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TIM14->SR = 0;
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/* Start the break sequence if idle */
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switch (tx_state) {
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case DMX_TX_IDLE:
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tx_state = DMX_TX_BREAK;
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/* Disable the DMA transfer */
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USART1->CR3 = 0ul;
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TIM14->CCR1 = dmx_tx_break_len;
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/* Send break */
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dmx_break(true);
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break;
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case DMX_TX_BREAK:
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/* Stop break pulse */
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dmx_break(false);
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TIM14->CCR1 = dmx_tx_break_len + dmx_tx_break_pause;
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tx_state = DMX_TX_BREAK_PAUSE;
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break;
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case DMX_TX_BREAK_PAUSE:
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tx_state = DMX_TX_IDLE;
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break;
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default:
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break;
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}
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} |