Hello everyone!
I'm trying to communicate with a slave device (ICM-42688-P: https://invensense.tdk.com/wp-content/uploads/2020/04/ds-000347_icm-42688-p-datasheet.pdf), but I don't recieve anything on the MISO line. I'm using the nucleo-wb55rg for the master device. The ICM-42688 typically needs 1.8V for the VDD and VDDIO, but the datasheet says it can be used between the range of 1.71V and 3.6V. Therefore I just used the nucleo's 3.3V pin output to power both. After that I configured the SPI following the datasheet:
The code I wrote for excercise is a read from the whoAmI register, which is at address 0x75 and contains the value of 0x47. However I only get 0s from the MISO line.
The code from main.c:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* Configure the peripherals common clocks */
PeriphCommonClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART1_UART_Init();
MX_USB_PCD_Init();
MX_MEMORYMAP_Init();
MX_SPI1_Init();
/* USER CODE BEGIN 2 */
char spi_buff[16] = {0};
uint8_t addr = 0x00;
uint8_t data[2] = {0};
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);
// Set bank addr 0x76
addr = 0x76;
data[1] = 0x00 | addr;
data[0] = 0x00;
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, (uint8_t *)data, 2, 100);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);
//Soft reset addr 0x11
addr = 0x11;
data[1] = 0x00 | addr;
data[0] = 0x01;
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, (uint8_t *)data, 2, 100);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);
HAL_Delay(1);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
// Get WhoIAM addr 0x75, value 0x47
addr = 0x75;
data[1] = 0x80 | addr;
data[0] = 0;
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, (uint8_t *)data, 2, 100);
HAL_SPI_Receive(&hspi1, (uint8_t *)spi_buff, 2, 100);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);
}
/* USER CODE END 3 */
}What am I missing here? Did I messed up something in the code or it is more likely a hardver issue?
I am looking forward for your answers!
Yours faithfully,
AndrasToth
I read the 0x40 in the software and I can see the following on the oscilloscope:
I configured it as you suggested (cpol high & cpha 2) using STM32CubeIde 1.13.2, but I can't find in the advanced parameters the Master keep IO state option.
Which .c file do I have to write a code that can manually enable this setting?
>What's that looking at?!
It was the reply on MISO line to the read command, but I'll capture a better one.
>You need to look at the full SPI transaction - is the slave actually sending 0x40, or 0x47, or ... ?
I did and that was the only signal.
>Also, does what your STM32 actually sends on the wires match the slave specs?
Yes it should be. The first bit of the first byte declare that the command will be a read(1) or write(0) command and next 7 bit is the address, which for the WhoAmI is 0x75.
The code I wrote for the transaction:
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
TxData[0] = 0x80 | 0x75;
TxData[1] = 0x00;
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
HAL_SPI_TransmitReceive(&hspi1, TxData, RxData, 2, 50);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);
}
/* USER CODE END 3 */Therefore I don't think this will be the problem, but I might be wrong here.
>Does your scope have the capability to decode SPI?
It can't unfortunately, I can only look at it deciper the signal myself.
The following pictures from the oscilloscope:
CLK:
CS:
MOSI ( 0x75 | 0x80 is 0b11110101 and I think this signal is exactly the same):
MISO:
