Posted on September 03, 2014 at 00:58I'm trying to run SPI on DMA Mode for STM32F407 (Discovery). I'm stuck with the below code, with the oscilloscope showing SPI CLK but no data. I'm wondering:
1. How do you do slave select in DMA Mode?
2. Is the DMA Channel for SPI2 right? I found this info before but forgot where it is.
3. If I want to do 2 SPI channels, both using DMA, is this possible?
Code:
#include <stm32f4xx_gpio.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_dma.h>
#include <stm32f4xx_spi.h>
#include <semihosting.h>
void Setup(void);
char SPI_Buffer[] = ''AAA'';
int main(void)
{
Setup();
while(1)
{
}
}
void Setup(void)
{
RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1 | RCC_AHB1Periph_GPIOB, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef SPI_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
//PB13 SPI2_SCK
//PB14 SPI2_MISO
//PB15 SPI2_MOSI
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB,&GPIO_InitStructure);
GPIO_PinAFConfig(GPIOB,GPIO_PinSource13,GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB,GPIO_PinSource14,GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB,GPIO_PinSource15,GPIO_AF_SPI2);
//Slave Select PC10
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_Init(GPIOC,&GPIO_InitStructure);
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //Should be Full Duplex
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; //SCK idle high
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge; //Second transition
SPI_InitStructure.SPI_NSS = SPI_NSS_Hard; //SPI_BaudRatePrescaler
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //SPI_CRCPolynomial
SPI_Init(SPI2, &SPI_InitStructure);
// DMA_DeInit(DMA1_Stream4);
DMA_InitStructure.DMA_Channel = DMA_Channel_0;
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral; //Transmit
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)SPI_Buffer;
DMA_InitStructure.DMA_BufferSize = (uint16_t)(sizeof(SPI_Buffer)-1);
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&SPI2->DR;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
//Setup the Dual Buffer mode for the Tx DMA
//DMA_DoubleBufferModeConfig(DMA1_Stream4, (uint32_t)SPI_Buffer, DMA_Memory_0);
//DMA_DoubleBufferModeCmd(DMA1_Stream4, ENABLE);
SPI_DMACmd(SPI2, SPI_DMAReq_Tx | SPI_DMAReq_Rx,ENABLE);
DMA_Init(DMA1_Stream4, &DMA_InitStructure);
DMA_Cmd(DMA1_Stream4, ENABLE);
}
