Posted on May 05, 2016 at 23:59
As you can see, the SPI interrupt is firing correctly after the first byte comes into the Rx buffer, but the DMA interrupt never fires.
Did I miss something with the DMA interrupt configuration? I have similar code driving DMA interrupts on a different application and it's working with no issues. Also, I'm not sure if I need to make the DMA wait and move one byte at a time instead of the whole buffer to prevent it trying to move data that hasn't yet made it to the SPI data register. This would certainly use more CPU cycles which is unfortunate in my application, I just don't know whether it's necessary or not. Either way, I'd still expect the TC interrupt to fire in the code I gave above.
Thanks for any help, and let me know if any additional details would be helpful.
Hi, I'm trying to get an STM32F0 read incoming data packets as a SPI slave using the DMA. I've been reading the DataExchangeDMA peripheral example code and trying to convert some of it to an interrupt driven model, but I have trouble getting the DMA to work correctly. I've boiled down my code to a simple program which should just move incoming SPI data to a buffer in RAM.
To debug, I'm running the code on an STM32F051 discovery board, and using the LED (PC8) to turn on between when the DMA completes a transfer and whenever the next byte comes in over SPI. Here's the code I'm working with:
#include ''stm32f0xx.h''
#define BUFFER_LEN 16
GPIO_InitTypeDef GPIO_InitStruct;
SPI_InitTypeDef SPI_InitStruct;
NVIC_InitTypeDef NVIC_InitStruct;
DMA_InitTypeDef DMA_InitStruct;
void
init(
void
);
uint8_t DataBuffer[BUFFER_LEN];
int
main(
void
)
{
init();
for
(;;)
{
}
}
void
init()
{
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_DMA1, ENABLE);
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
// Discovery LED
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_Init(GPIOC, &GPIO_InitStruct);
GPIO_SetBits(GPIOC, GPIO_Pin_8);
// SPI pins
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_0);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_0);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_0);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_0);
// SPI peripheral setup
SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStruct.SPI_Mode = SPI_Mode_Slave;
SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitStruct.SPI_NSS = SPI_NSS_Hard;
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2;
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStruct.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStruct);
SPI_RxFIFOThresholdConfig(SPI1, SPI_RxFIFOThreshold_QF);
SPI_Cmd(SPI1, ENABLE);
// SPI interrupt config
NVIC_InitStruct.NVIC_IRQChannel = SPI1_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPriority = 1;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, ENABLE);
// DMA setup
DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;
DMA_InitStruct.DMA_M2M = DMA_M2M_Disable;
DMA_InitStruct.DMA_BufferSize = BUFFER_LEN;
DMA_InitStruct.DMA_MemoryBaseAddr = (uint32_t)DataBuffer;
DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStruct.DMA_Priority = DMA_Priority_High;
DMA_InitStruct.DMA_PeripheralBaseAddr = 0x4001300C;
// SPI1 peripheral DR register address
DMA_Init(DMA1_Channel2, &DMA_InitStruct);
// DMA interrupt config
NVIC_InitStruct.NVIC_IRQChannel = DMA1_Channel2_3_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPriority = 3;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Rx, ENABLE);
DMA_ITConfig(DMA1_Channel2, DMA_IT_TC, ENABLE);
}
void
DMA1_Channel2_3_IRQHandler()
{
GPIO_SetBits(GPIOC, GPIO_Pin_8);
if
(DMA_GetFlagStatus(DMA1_FLAG_TC2))
{
SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, ENABLE);
DMA_Cmd(DMA1_Channel2, DISABLE);
DMA_SetCurrDataCounter(DMA1_Channel2, BUFFER_LEN);
DMA_ClearFlag(DMA1_FLAG_TC2);
}
}
void
SPI1_IRQHandler()
{
GPIO_ResetBits(GPIOC, GPIO_Pin_8);
if
(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE))
{
SPI_I2S_ClearFlag(SPI1, SPI_I2S_FLAG_RXNE);
SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, DISABLE);
DMA_Cmd(DMA1_Channel2, ENABLE);
}
}
void
assert_failed(
const
char
* file,
const
int
line)
{
for
(;;);
}