We use STM32F746 discovery board and run stm32f7 as spi slave with nss as sync signal between each byte. The master drives nss, clk and mosi pins. Clock is 250khz and processing is done in interrupt. Every 100ms 1 byte is transferred. Sometimes the slave misses single bytes.
Init code is shown below.
void HAL_SPI_MspInit(SPI_HandleTypeDef *hspi)
{
GPIO_InitTypeDef GPIO_InitStruct;
if (hspi->Instance == SPIx)
{
/*##-1- Enable peripherals and GPIO Clocks #################################*/
/* Enable GPIO TX/RX clock */
SPIx_SCK_GPIO_CLK_ENABLE();
SPIx_NSS_GPIO_CLK_ENABLE();
SPIx_MISO_GPIO_CLK_ENABLE();
SPIx_MOSI_GPIO_CLK_ENABLE();
/* Enable SPI clock */
SPIx_CLK_ENABLE();
/*##-2- Configure peripheral GPIO ##########################################*/
/* SPI SCK GPIO pin configuration */
GPIO_InitStruct.Pin = SPIx_SCK_PIN;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
GPIO_InitStruct.Alternate = SPIx_SCK_AF;
HAL_GPIO_Init(SPIx_SCK_GPIO_PORT, &GPIO_InitStruct);
/* SPI MISO GPIO pin configuration */
GPIO_InitStruct.Pin = SPIx_MISO_PIN;
GPIO_InitStruct.Alternate = SPIx_MISO_AF;
HAL_GPIO_Init(SPIx_MISO_GPIO_PORT, &GPIO_InitStruct);
/* SPI MOSI GPIO pin configuration */
GPIO_InitStruct.Pin = SPIx_MOSI_PIN;
GPIO_InitStruct.Alternate = SPIx_MOSI_AF;
HAL_GPIO_Init(SPIx_MOSI_GPIO_PORT, &GPIO_InitStruct);
/* SPI NSS GPIO pin configuration */
GPIO_InitStruct.Pin = SPIx_NSS_PIN;
GPIO_InitStruct.Alternate = SPIx_NSS_AF;
HAL_GPIO_Init(SPIx_NSS_GPIO_PORT, &GPIO_InitStruct);
/*##-3- Configure the NVIC for SPI #########################################*/
/* NVIC for SPI */
HAL_NVIC_SetPriority(SPIx_IRQn, 1, 0);
HAL_NVIC_EnableIRQ(SPIx_IRQn);
}
}
static void SpiInit()
{
SpiHandle.Instance = SPIx;
SpiHandle.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_256;
SpiHandle.Init.Direction = SPI_DIRECTION_2LINES;
SpiHandle.Init.CLKPhase = SPI_PHASE_1EDGE;
SpiHandle.Init.CLKPolarity = SPI_POLARITY_LOW;
SpiHandle.Init.DataSize = SPI_DATASIZE_8BIT;
SpiHandle.Init.FirstBit = SPI_FIRSTBIT_MSB;
SpiHandle.Init.TIMode = SPI_TIMODE_DISABLE;
SpiHandle.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
SpiHandle.Init.CRCPolynomial = 7;
SpiHandle.Init.NSS = SPI_NSS_HARD_INPUT;
SpiHandle.Init.Mode = SPI_MODE_SLAVE;
if(HAL_SPI_Init(&SpiHandle) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
}
Voltage on ports is 3,3 volts. When we connect oscilloscope on nss pin, no more data is lost?!?! Could be a problem with ground level or VCC??? When we use software slave management everything works fine. Any idea what causes the problem?
Thanks in advance
