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单片机源程序如下:
- #include "WS2812B.h"
- /* Buffer that holds one complete DMA transmission
- *
- * Ensure that this buffer is big enough to hold
- * all data bytes that need to be sent
- *
- * The buffer size can be calculated as follows:
- * number of LEDs * 24 bytes + 42 bytes
- *
- * This leaves us with a maximum string length of
- * (2^16 bytes per DMA stream - 42 bytes)/24 bytes per LED = 2728 LEDs
- */
- //#define TIM3_CCR3_Address 0x4000043c // physical memory address of Timer 3 CCR1 register
- //#define TIM3_CCR1_Address 0x40000434 // physical memory address of Timer 3 CCR1 register
- #define TIM2_CCR1_Address 0x40000034
-
- #define TIMING_ONE 50
- #define TIMING_ZERO 25
- uint16_t LED_BYTE_Buffer[300];
- //---------------------------------------------------------------//
- void Timer2_init(void)
- {
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- TIM_OCInitTypeDef TIM_OCInitStructure;
- GPIO_InitTypeDef GPIO_InitStructure;
- DMA_InitTypeDef DMA_InitStructure;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
- /* GPIOA Configuration: TIM2 Channel 1 as alternate function push-pull */
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOA, &GPIO_InitStructure);
-
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
- /* Compute the prescaler value */
- //PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;
- /* Time base configuration */
- TIM_TimeBaseStructure.TIM_Period = 90-1; // 800kHz
- TIM_TimeBaseStructure.TIM_Prescaler = 0;
- TIM_TimeBaseStructure.TIM_ClockDivision = 0;
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
- TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
- /* PWM1 Mode configuration: Channel1 */
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
- TIM_OCInitStructure.TIM_Pulse = 0;
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
- TIM_OC1Init(TIM2, &TIM_OCInitStructure);
-
- /* configure DMA */
- /* DMA clock enable */
- RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
-
- /* DMA1 Channel6 Config */
- DMA_DeInit(DMA1_Channel2);
- DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)TIM2_CCR1_Address; // physical address of Timer 3 CCR1
- DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)LED_BYTE_Buffer; // this is the buffer memory
- DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST; // data shifted from memory to peripheral
- DMA_InitStructure.DMA_BufferSize = 42;
- DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
- DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; // automatically increase buffer index
- DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
- DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
- DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; // stop DMA feed after buffer size is reached
- DMA_InitStructure.DMA_Priority = DMA_Priority_High;
- DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
-
- DMA_Init(DMA1_Channel2, &DMA_InitStructure);
- /* TIM3 CC1 DMA Request enable */
- TIM_DMACmd(TIM2, TIM_DMA_Update, ENABLE);
- }
- /* This function sends data bytes out to a string of WS2812s
- * The first argument is a pointer to the first RGB triplet to be sent
- * The seconds argument is the number of LEDs in the chain
- *
- * This will result in the RGB triplet passed by argument 1 being sent to
- * the LED that is the furthest away from the controller (the point where
- * data is injected into the chain)
- */
- void WS2812_send(uint8_t (*color)[3], uint16_t len)
- {
- uint8_t i;
- uint16_t memaddr;
- uint16_t buffersize;
- buffersize = (len*24)+43; // number of bytes needed is #LEDs * 24 bytes + 42 trailing bytes
- memaddr = 0; // reset buffer memory index
- while (len)
- {
- for(i=0; i<8; i++) // GREEN data
- {
- LED_BYTE_Buffer[memaddr] = ((color[0][1]<<i) & 0x0080) ? TIMING_ONE:TIMING_ZERO;
- memaddr++;
- }
- for(i=0; i<8; i++) // RED
- {
- LED_BYTE_Buffer[memaddr] = ((color[0][0]<<i) & 0x0080) ? TIMING_ONE:TIMING_ZERO;
- memaddr++;
- }
- for(i=0; i<8; i++) // BLUE
- {
- LED_BYTE_Buffer[memaddr] = ((color[0][2]<<i) & 0x0080) ? TIMING_ONE:TIMING_ZERO;
- memaddr++;
- }
-
- len--;
- }
- //===================================================================//
- //bug：最后一个周期波形不知道为什么全是高电平，故增加一个波形
- LED_BYTE_Buffer[memaddr] = ((color[0][2]<<8) & 0x0080) ? TIMING_ONE:TIMING_ZERO;
- //===================================================================//
- memaddr++;
- while(memaddr < buffersize)
- {
- LED_BYTE_Buffer[memaddr] = 0;
- memaddr++;
- }
- DMA_SetCurrDataCounter(DMA1_Channel2, buffersize); // load number of bytes to be transferred
- DMA_Cmd(DMA1_Channel2, ENABLE); // enable DMA channel 6
- TIM_Cmd(TIM2, ENABLE); // enable Timer 3
- while(!DMA_GetFlagStatus(DMA1_FLAG_TC2)) ; // wait until transfer complete
- TIM_Cmd(TIM2, DISABLE); // disable Timer 3
- DMA_Cmd(DMA1_Channel2, DISABLE); // disable DMA channel 6
- DMA_ClearFlag(DMA1_FLAG_TC2); // clear DMA1 Channel 6 transfer complete flag
- }
所有资料51hei提供下载:
STM32F1_DMA_PWM_WS2813E_2018_05_06.rar
(282.3 KB, 下载次数: 296)
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