STM32F1 (stm32vldiscovery) - Can't make SPI work

[Bob jenkins]

Posted on January 12, 2017 at 15:27

Hello

I am trying to get SPI working on stm32vldiscovery.In my project I am using STM32 Peripheral Library (SPL), not HAL.For now I am trying to make SPI1 send data to SPI2, SPI2 echoes everything back to SPI1, and SPI1 sends the received data to USART1, so I can see the output in a serial terminal app.I also have a logic analyzer connected to both USART1 and 4 SPI lines (ss, mosi, miso, clk).What I see is USART always sending 0xff bytes (instead of the actual bytes I am sending to SPI), and there are one less byte than I actually send with SPI. USART sends other non-spi related bytes correctly.SPI1 is configured as Master, SPI2 is configured as Slave.What is wrong with the following code?USART is set up and functioning correctly. I am getting 'Application started' when I launch the program. Something must be wrong with the SPI settings but I can't figure out what.

Thanks for your help!

//Initializing SPI1 as master

//SPI1 SS(PA4), SCK(PA5), MISO(PA6), MOSI(PA7)

&sharpdefine SPI1_SS GPIO_Pin_4

&sharpdefine SPI1_SCK GPIO_Pin_5&sharpdefine SPI1_MISO GPIO_Pin_6&sharpdefine SPI1_MOSI GPIO_Pin_7

//Clock

RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

//GPIO (for SPI1)

GPIO_InitTypeDef spiGpioInitStruct; spiGpioInitStruct.GPIO_Pin = SPI1_SCK | SPI1_MOSI | SPI1_SS; spiGpioInitStruct.GPIO_Speed = GPIO_Speed_50MHz; spiGpioInitStruct.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_Init(GPIOA, &spiGpioInitStruct); spiGpioInitStruct.GPIO_Pin = SPI1_MISO; spiGpioInitStruct.GPIO_Speed = GPIO_Speed_50MHz; spiGpioInitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOA, &spiGpioInitStruct);

//Initializing SPI itself

SPI_InitTypeDef spiInitStruct; spiInitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; spiInitStruct.SPI_DataSize = SPI_DataSize_8b; spiInitStruct.SPI_CPOL = SPI_CPOL_Low; spiInitStruct.SPI_CPHA = SPI_CPHA_1Edge; spiInitStruct.SPI_NSS = SPI_NSS_Hard; spiInitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32; spiInitStruct.SPI_FirstBit = SPI_FirstBit_MSB; spiInitStruct.SPI_Mode = SPI_Mode_Master; SPI_Init(SPI1, &spiInitStruct); SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, ENABLE); SPI_Cmd(SPI1, ENABLE); NVIC_EnableIRQ(SPI1_IRQn);

//Initializing SPI2 as slave

//SPI2 SS(PB12), SCK(PB13), MISO(PB14), MOSI(PB15)

&sharpdefine SPI2_SS GPIO_Pin_12

&sharpdefine SPI2_SCK GPIO_Pin_13&sharpdefine SPI2_MISO GPIO_Pin_14&sharpdefine SPI2_MOSI GPIO_Pin_15

//Clock

RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); //GPIO (for SPI2) GPIO_InitTypeDef spi2GpioInitStruct; spi2GpioInitStruct.GPIO_Pin = SPI2_MISO | SPI2_SS; spi2GpioInitStruct.GPIO_Speed = GPIO_Speed_50MHz; spi2GpioInitStruct.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_Init(GPIOB, &spi2GpioInitStruct); spi2GpioInitStruct.GPIO_Pin = SPI2_SCK | SPI2_MOSI; spi2GpioInitStruct.GPIO_Speed = GPIO_Speed_50MHz; spi2GpioInitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOB, &spi2GpioInitStruct);

//Initializing SPI itself

SPI_InitTypeDef spi2InitStruct; spi2InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; spi2InitStruct.SPI_DataSize = SPI_DataSize_8b; spi2InitStruct.SPI_CPOL = SPI_CPOL_Low; spi2InitStruct.SPI_CPHA = SPI_CPHA_1Edge; spi2InitStruct.SPI_NSS = SPI_NSS_Hard; spi2InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32; spi2InitStruct.SPI_FirstBit = SPI_FirstBit_MSB; spi2InitStruct.SPI_Mode = SPI_Mode_Slave; SPI_Init(SPI2, &spi2InitStruct); SPI_I2S_ITConfig(SPI2, SPI_I2S_IT_RXNE, ENABLE); SPI_Cmd(SPI2, ENABLE); NVIC_EnableIRQ(SPI2_IRQn);

sendStringToUart('Application started\n');

char *buf = 'oh well this is it';

while(1) {

if(*buf) { while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) != SET); SPI_I2S_SendData(SPI1, (uint16_t)*buf); buf++; }

processUsartRxBuffer();

}}

//Master SPI

void SPI1_IRQHandler() { if(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == SET) { //this is RX not empty (i.e., byte received) uint8_t receivedByte = SPI1->DR; //... do something with the received byte sendBufToUart(&receivedByte, 1); //lets send it to UART and print in terminal //i++; }}

//Slave SPI

void SPI2_IRQHandler() { if(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == SET) { //this is RX not empty (i.e., byte received) uint8_t receivedByte = SPI_I2S_ReceiveData(SPI2); //... do something with the received byte while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) != SET); //wait for previous transmission to be completed SPI_I2S_SendData(SPI2, receivedByte); //just echo what slave has received from master //SPI2->DR = receivedByte;

}

}

Thank you.

#spi #stm32f1 #stm32f1-spi

[Imen.D]

Posted on January 13, 2017 at 09:36

Hello

jenkins.bob

‌, I suggest you to have a look at the SPI example under the STM32F1 standard peripheral library that can help to build your project and have more idea about SPI configuration:

STM32F10x_StdPeriph_Lib_V3.5.0\Project\STM32F10x_StdPeriph_Examples\SPI

You can refer to the manual

http://www.st.com/content/ccc/resource/technical/document/reference_manual/a2/2d/02/4b/78/57/41/a3/CD00246pdf/files/CD00246pdf/jcr:content/translations/en.CD00246pdf

, exactly in section 'Serial peripheral interface (SPI)' for more details/clarification. Also, check if you have the same condition as described in the

http://www.st.com/content/ccc/resource/technical/document/errata_sheet/a9/f2/ac/eb/22/6b/4f/70/CD00260pdf/files/CD00260pdf/jcr:content/translations/en.CD00260pdf

related to SPI limitation for your device.

Hope this helps you.

Thanks