Posted on May 25, 2018 at 13:45 Background
(note I asked this question too at
https://electronics.stackexchange.com/questions/376282/how-to-receive-bytes-from-spi-with-interrupts-using-hal-on-stm32
, but no answers yet).
I am trying to make a SPI connection between two STM32F103C8T6's.
Measurements
According to my logic analyzer I get a signal that looks ok (sending 10 bytes with values 0x55):
Results
My receiver's callback function for RX Complete also stops in the breakpoint (last line in code below):
void HAL_SPI_RxCpltCallback(SPI_HandleTypeDef *hspi)
{
/* Prevent unused argument(s) compilation warning */
if (hspi1.RxXferCount == 10)
Problem
I sent 10 bytes, however, the RxXferCount has value 0. Instead, RxXferSize has value 10, but pRxBuffPtr is empty.
Question
How can I receive the correct bytes?
**Values from the register SPI1 and variable hspi1**
https://i.stack.imgur.com/xb5X5.png
Relevant code
Initialization (using a GPIO for defining Master and Slave):
/* SPI1 init function */
static void MX_SPI1_Init(void)
{
hspi1.Instance = SPI1;
hspi1.Init.Mode = (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_12) == GPIO_PIN_SET ?
SPI_MODE_MASTER : SPI_MODE_SLAVE);
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_256;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
Main function:
int main(void)
{
...
MX_SPI1_Init();
...
_transmitter = (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_12) == GPIO_PIN_SET ?
SPI_MODE_MASTER : SPI_MODE_SLAVE);
while (1)
{
if (_transmitter)
{
uint8_t data[] = { 0x55, 0x55, 0x55, 0x55, 0x55,
0x55, 0x55, 0x55, 0x55, 0x55 };
HAL_SPI_Transmit_IT(&hspi1, data, 10);
}
else
{
HAL_SPI_Receive_IT(&hspi1, _spi_data, 10);
}
}
}
