Getting Started with STM32H5 ARM Cortex M33: SPI in Full Duplex Mode

In this guide, we shall cover how to transmit and receive data from a slave device connected to out STM32H5. The slave device is ADXL345 accelerometer.

In this guide, we shall cover the following:

• Configure SPI for ADXL345.
• ADXL345 connection.
• Modification to the library.
• Results.

1. Configure the SPI for ADXL345:

Open SPI_TX.ioc file as following:

From connectivity, select the SPI and configure it as following:

Keep the baudrate as it since it will work just fine.

Set the following:

• Clock Polarity (CPOL) to High.
• Clock Phase (CPHA) tp 2 Edge.

From the pins, give PA6 a name as CS as following:

Save the project and this will generate the project again.

2. ADXL345 Connection:

The sensor shall be connected as following:

3. Modification to the Library:

Next, head to this guide here or simply, download the entire code from here:

in ADXL345.c source file, include the main.h as following:

#include "main.h"

For CS line, read and write to the sensor functions:

static void cs_enable()
{
	HAL_GPIO_WritePin(CS_GPIO_Port, CS_Pin, 0);
}

static void cs_disable()
{
	HAL_GPIO_WritePin(CS_GPIO_Port, CS_Pin, 1);
}



static void adxl345_write(uint8_t address, uint8_t value)
{
	uint8_t data[2];

	/*Enable multi-byte, place address into buffer*/
	data[0] = address|MULTI_BYTE_EN;

	/*Place data into buffer*/
	data[1] = value;

	/*Pull cs line low to enable slave*/
	cs_enable();

	/*Transmit data and address*/

	HAL_SPI_Transmit(&hspi1, data, 2, 100);


	/*Pull cs line high to disable slave*/
	cs_disable();


}

static void adxl345_read(uint8_t address, uint8_t * rxdata)
{

	/*Set read operation*/
	address |= READ_OPERATION;

	/*Enable multi-byte*/
	address |= MULTI_BYTE_EN;

	uint8_t DummyBuffer[6];

	DummyBuffer[0]=address;

	for (int i=1;i<5;i++)
	{
		DummyBuffer[i]=0xFF;
	}


	/*Pull cs line low to enable slave*/
	cs_enable();

	HAL_SPI_TransmitReceive(&hspi1, DummyBuffer, rxdata, 6, 300);

	/*Pull cs line high to disable slave*/
	cs_disable();

}

The rest of the code shall remain the same, except removing the following functions from the initialization function of the sensor:

adxl_spi_pins_init();
adxl_spi_config();

In main.c file:

first include the adxl library as following:

#include "adxl345.h"

Declare the acceleration data structure to handle the acceleration as following:

accleration_values_t accleration_values;

In the main function, initialize the sensor as following:

adxl345_init(accl_4g);

In the while loop, update the sensor values as following:

adxl345_update();
adxl345_get_values(&accleration_values);

Save the project, build it and run it on your STM32H563Zi board.

4. Results:

By probing the 4pins using oscilloscope or logic analyzer, we can find that we have successfully send 6 bytes of data and receive 6 bytes of data from the sensor.

Happy coding 😉