Implement first draft of working DMX. Still needs rework and beatifying

firmware/dmx.c

@@ -8,15 +8,14 @@ enum dmx_rx_state_enum {
 	DMX_RX_DATA,
 };
 
+static volatile bool break_received;
+
 /**
  * @brief DMX data received. Contains the whole DMX universe including the first 0 byte.
  * The controller does check the first byte to be zero.
  */
 static volatile uint8_t dmx_channel_data[DMX_UNIVERSE_SIZE + 1];
 
-static volatile enum dmx_rx_state_enum dmx_rx_state;
-static volatile uint32_t dmx_write_pointer;
-
 void dmx_init(uint32_t base_channel)
 {
 	int i;
@@ -27,11 +26,10 @@ void dmx_init(uint32_t base_channel)
 	}
 
 	dmx_base_channel = base_channel;
-	dmx_write_pointer = 0u;
+	break_received = false;
-	dmx_rx_state = DMX_RX_WAIT_FOR_BREAK;
 
 	/* Enable GPIOA and USART1 clock */
-	RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
+	RCC->AHBENR |= RCC_AHBENR_GPIOAEN | RCC_AHBENR_DMAEN;
 	RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
 
 	/* Switch RXTX pin low, activating permanent READ mode */
@@ -51,49 +49,78 @@ void dmx_init(uint32_t base_channel)
 	/* Map USART1 RX to DMA Channel 3 */
 	SYSCFG->CFGR1 &= ~SYSCFG_CFGR1_USART1RX_DMA_RMP;
 
+	DMA1_Channel3->CCR = DMA_CCR_PL_1 | DMA_CCR_MINC | DMA_CCR_TCIE;
+
+	NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
 	NVIC_EnableIRQ(USART1_IRQn);
 }
 
 
 const uint8_t *dmx_get_data()
 {
-	return (const uint8_t *)&dmx_channel_data[1];
+	return (const uint8_t *)dmx_channel_data;
 }
 
 void USART1_IRQHandler(void)
 {
 	uint32_t isr;
-	uint8_t dreg;
 
 	isr = USART1->ISR;
 	USART1->ICR = USART_ICR_ORECF | USART_ICR_NCF | USART_ICR_FECF;
 
 	if (isr & USART_ISR_FE) {
 		/* Frame error received. Start of DMX frame */
-		dmx_write_pointer = 0u;
-		dmx_rx_state = DMX_RX_DATA;
 		/* Flush RX data */
 		USART1->RQR = USART_RQR_RXFRQ;
+		USART1->CR3 |= USART_CR3_DMAR;
+		DMA1_Channel3->CCR &= ~DMA_CCR_EN;
+		DMA1_Channel3->CMAR = (uint32_t)dmx_channel_data;
+		DMA1_Channel3->CPAR = (uint32_t)&USART1->RDR;
+		DMA1_Channel3->CNDTR = DMX_UNIVERSE_SIZE + 1;
+		DMA1_Channel3->CCR |= DMA_CCR_EN;
+		USART1->CR3 |= USART_CR3_DMAR;
+		break_received = true;
 	} else if (isr & USART_ISR_RXNE) {
-		/* Received valid symbol */
-		dreg = (uint8_t)USART1->RDR;
-
-		if (dmx_rx_state == DMX_RX_DATA) {
-			/* Ready to recieve data */
-			if (dmx_write_pointer < (DMX_UNIVERSE_SIZE + 1)) {
-				dmx_channel_data[dmx_write_pointer] = dreg;
-				dmx_write_pointer++;
-			} else {
-				dmx_rx_state = DMX_RX_WAIT_FOR_BREAK;
-			}
-		}
 
 	}
 
 	__DSB();
 }
 
-void DMA_CH2_3_DMA2_CH1_2_IRQHandler()
+void DMA_CH2_3_DMA2_CH1_2_IRQHandler(void)
 {
+	uint32_t isr;
 
+	isr = DMA1->ISR;
+	/* Only clear the interupts of channel 2 (bits 11:9) */
+	DMA1->IFCR = isr & 0xF00;
+
+	if (isr & DMA_ISR_TCIF3) {
+		DMA1->ISR;
+	}
+	__DSB();
+}
+
+bool dmx_poll_break_received(void)
+{
+	bool ret;
+
+	/* Atomically reset the flag */
+	__disable_irq();
+	ret = break_received;
+	break_received = false;
+	__enable_irq();
+
+	return ret;
+}
+
+bool dmx_enough_data_received()
+{
+	uint32_t received_count = (DMX_UNIVERSE_SIZE + 1) - DMA1_Channel3->CNDTR;
+
+	if (received_count > (dmx_base_channel + DMX_USED_CHANNEL_COUNT)) {
+		return true;
+	}
+
+	return false;
 }

firmware/include/ring-light/dmx.h

@@ -34,4 +34,16 @@ void dmx_init(uint32_t base_channel);
  */
 const uint8_t *dmx_get_data(void);
 
+/**
+ * @brief Check if a break was received. This resets the flag
+ * @return true if a break was received since the last time calling this function
+ */
+bool dmx_poll_break_received(void);
+
+/**
+ * @brief The DMX receiver has received all data for the ring light. It can be read
+ * @return
+ */
+bool dmx_enough_data_received(void);
+
 #endif /* _DMX_H_ */

firmware/main.c

@@ -16,7 +16,9 @@ enum ring_modes {
 	RING_MODE_ARC,                  /*!< SK6812 closing ring */
 	RING_MODE_QUARTER,              /*!< SK6812 walking quarter */
 	RING_MODE_IN_FARBE_UND_BUNT,    /*!< SK6812 color mix */
-	RING_MODE_MAX                   /*!< end of list */
+	RING_MODE_MAX,                   /*!< end of list */
+	RING_MODE_WAIT_DMX,
+	RING_MODE_WAIT_DMX_BREAK
 };
 
 volatile int32_t temperature;
@@ -34,10 +36,13 @@ static void wait_for_ticks(uint32_t ticks)
 int main(void)
 {
 	uint32_t led_val = 0x00UL;
+	uint32_t last_led_val = 0x00UL;
 	uint32_t led_calc_val[RING_MAX_LED] = {0x00UL};
 	uint8_t led_pwm_val = 0u;
+	const uint8_t *dmx_data;
 
 	bool button_pressed = false;
+	bool force_led_update;
 	enum ring_modes mode;
 
 	RCC->AHBENR |= RCC_AHBENR_GPIOAEN | RCC_AHBENR_GPIOBEN;
@@ -88,14 +93,23 @@ int main(void)
 
 	SysTick_Config(800000);
 	while(1) {
+		force_led_update = false;
 		temperature = temperature_adc_get_temp();
 
+		if (led_val != last_led_val || button_pressed) {
+			force_led_update = true;
+		}
+
 		/*! -# Gradually dim down the LED brightness in case the temperature is too high */
 		if (temperature > ((MAX_TEMP_CELSIUS) * 10)) {
 			if (led_val > 20)
 				led_val--;
 		}
 
+		if (dmx_poll_break_received()) {
+			mode = RING_MODE_WAIT_DMX;
+		}
+
 		led_pwm_val = 0u;
 		switch (mode)
 		{
@@ -165,6 +179,26 @@ int main(void)
 				}
 			}
 			break;
+		case RING_MODE_WAIT_DMX:
+			force_led_update = false;
+			if (dmx_enough_data_received()) {
+				dmx_data = dmx_get_data();
+				mode = RING_MODE_WAIT_DMX_BREAK;
+				if (dmx_data[0] != 0)
+					break;
+				for (int i = 0; i < RING_MAX_LED; i++) {
+					led_calc_val[i] = (dmx_data[1 + i*4 + 3]) |
+							(dmx_data[1 + i*4 + 2] << 8) |
+							(dmx_data[1 + i*4 + 0] << 16) |
+							(dmx_data[1 + i*4 + 1] << 24);
+				}
+				led_pwm_val = dmx_data[129];
+				force_led_update = true;
+			}
+			break;
+		case RING_MODE_WAIT_DMX_BREAK:
+			force_led_update = false;
+			break;
 		default:
 			for(int i = 0; i < RING_MAX_LED; i ++) {
 				led_calc_val[i] = 0x00000000UL;
@@ -172,30 +206,35 @@ int main(void)
 			break;
 		}
 
-		TIM14->CCR1 = led_pwm_val;
+		if (force_led_update) {
+			TIM14->CCR1 = led_pwm_val;
 
-		for(int i = 0; i < RING_MAX_LED; i ++) {
+			for(int i = 0; i < RING_MAX_LED; i ++) {
-			/* Allow interrupts in between LEDs.
+				/* Allow interrupts in between LEDs.
-			 * They must not exceed the reset length of 80us of SK6812.
+				 * They must not exceed the reset length of 80us of SK6812.
-			 */
+				 */
-			__disable_irq();
+				__disable_irq();
-			sk6812_send_led(led_calc_val[i]);
+				sk6812_send_led(led_calc_val[i]);
-			__enable_irq();
+				__enable_irq();
+			}
+			last_led_val = led_val;
 		}
 
+
+
 		wait_for_ticks(5);
 
 		if((int16_t)TIM3->CNT > (int16_t)led_val) {
 			led_val = 0u;
-		}
+		} else if(((int16_t)led_val - (int16_t)TIM3->CNT) > UINT8_MAX) {
-		else if(((int16_t)led_val - (int16_t)TIM3->CNT) > UINT8_MAX) {
 			led_val = 255u;
-		}
+		} else {
-		else {
 			led_val = (int16_t)led_val - (int16_t)TIM3->CNT;
 		}
+
 		TIM3->CNT = 0u;
 
+
 		if(button_pressed) {
 			if(GPIOA->IDR & GPIO_IDR_0) {
 				button_pressed = false;