Working on driving WS2812B's with DMA.

sandbox/sandbox.c

@@ -3,9 +3,23 @@
 
 #include "ch32v00x.h"
 #include <stdio.h>
+#include <string.h>
 
 #define APB_CLOCK SYSTEM_CORE_CLOCK
 
+// Working on WS2812 driving.
+
+// For debug writing to the UART.
+int _write(int fd, char *buf, int size)
+{
+    for(int i = 0; i < size; i++){
+        while( !(USART1->STATR & USART_FLAG_TC));
+        USART1->DATAR = *buf++;
+    }
+    return size;
+}
+
+
 void SystemInit(void)
 {
 	// Values lifted from the EVT.  There is little to no documentation on what this does.
@@ -25,12 +39,70 @@ void SystemInit(void)
 	RCC->CFGR0 = ( RCC->CFGR0 & ((uint32_t)~(RCC_SW))) | (uint32_t)RCC_SW_PLL;					// Select PLL as system clock source
 	while ((RCC->CFGR0 & (uint32_t)RCC_SWS) != (uint32_t)0x08);									// Wait till PLL is used as system clock source
 
+	// Once clock is up and running, we can enable the UART for other debugging.
+
+	// Enable GPIOD and UART.
+	RCC->APB2PCENR |= RCC_APB2Periph_GPIOD | RCC_APB2Periph_USART1;
 
+	// Push-Pull, 10MHz Output, GPIO D5, with AutoFunction
+	GPIOD->CFGLR &= ~(0xf<<(4*5));
+	GPIOD->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP_AF)<<(4*5);
+	
+	// 115200, 8n1.  Note if you don't specify a mode, UART remains off even when UE_Set.
+	USART1->CTLR1 = USART_WordLength_8b | USART_Parity_No | USART_Mode_Tx;
+	USART1->CTLR2 = USART_StopBits_1;
+	USART1->CTLR3 = USART_HardwareFlowControl_None;
+
+	#define UART_BAUD_RATE 115200
+	#define OVER8DIV 4
+	#define INTEGER_DIVIDER (((25 * (APB_CLOCK)) / (OVER8DIV * (UART_BAUD_RATE))))
+	#define FRACTIONAL_DIVIDER ((INTEGER_DIVIDER)%100)
+	USART1->BRR = ((INTEGER_DIVIDER / 100) << 4) | ((((FRACTIONAL_DIVIDER * (OVER8DIV*2)) + 50)/100)&7);
+	USART1->CTLR1 |= CTLR1_UE_Set;
 }
 
-int main()
+
+uint16_t bufferset[128];
+
+void ConfigSpeedyLED()
 {
+	RCC->AHBPCENR |= RCC_AHBPeriph_DMA1;
+	RCC->APB2PCENR |= RCC_APB2Periph_GPIOC | RCC_APB2Periph_SPI1;
+
+	// MOSI
+	GPIOC->CFGLR &= ~(0xf<<(4*6));
+	GPIOC->CFGLR |= (GPIO_Speed_50MHz | GPIO_CNF_OUT_PP_AF)<<(4*6);
+
+	SPI1->CTLR1 = 
+		SPI_NSS_Hard | SPI_CPHA_1Edge | SPI_CPOL_Low | SPI_DataSize_16b |
+		SPI_Mode_Master | SPI_NSS_Soft | SPI_Direction_1Line_Tx |
+		3<<3; // Dvisior
 
+	SPI1->CTLR2 = SPI_CTLR2_TXDMAEN;
+	SPI1->HSCR = 1;
+
+	SPI1->CTLR1 |= CTLR1_SPE_Set;
+
+	memset( bufferset, 0xaa, sizeof( bufferset ) );
+
+	//DMA1_Channel3 is for SPI1TX
+	DMA1_Channel3->PADDR = (uint32_t)&SPI1->DATAR;
+	DMA1_Channel3->MADDR = (uint32_t)bufferset;
+	DMA1_Channel3->CNTR  = sizeof( bufferset )/2; // Number of unique copies.
+	DMA1_Channel3->CFGR  =
+		DMA_M2M_Disable |		 
+		DMA_Priority_VeryHigh |
+		DMA_MemoryDataSize_HalfWord |
+		DMA_PeripheralDataSize_HalfWord |
+		DMA_MemoryInc_Enable |
+		DMA_Mode_Normal | // OR DMA_Mode_Circular
+		DMA_DIR_PeripheralDST;
+
+	DMA1_Channel3->CFGR |= DMA_CFGR1_EN;
+}
+
+int main()
+{
 	// PLL + Prescale down ADC
 //	RCC->CFGR0 = RCC_SW_PLL | RCC_SWS_PLL | RCC_ADCPRE_DIV8;
 //	RCC->CTLR = RCC_PLLON | RCC_HSION | 0xff00;
@@ -54,8 +126,13 @@ int main()
 	GPIOD->CFGLR &= ~(0xf<<(4*6));
 	GPIOD->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP)<<(4*6);
 
+	ConfigSpeedyLED();
+
+	printf( "CFG: %08x\n", SPI1->CTLR1 );
+
 	while(1)
 	{
+
 		GPIOD->BSHR = 128+64+1;
 		GPIOD->BSHR = 1<<16;
 		GPIOD->BSHR = 1;