SPI master cannot receive SPI slave response

RE: SPI master cannot receive SPI slave response

hmolesworth — Thu, 03 May 2018 15:41:16 GMT

The problem starts with a simple coding mistake mixing up variables and pointers to variables. You can find some more information on a recent post here.

Without changing the intent of your code, start by correctly specifying the send_recv function (lots of ways to do this, just a starting point; this is pretty horrible, I'm just trying to point out the issues with the original code.

static void spi_send_recv(const nrf_drv_spi_t *spi_master_instance, uint8_t *p_tx_data, uint8_t *p_rx_data,const uint16_t len)
{
 uint32_t err_code = nrf_drv_spi_transfer(spi_master_instance, p_tx_data, len, p_rx_data, len);
}

Next pass the address of the variables, not the values:

// Assuming static const nrf_drv_spi_t SPI_INSTANCE_0 = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);

uint8_t dummy_tx = 0xA0;
 spi_send_recv(&SPI_MASTER_0, &dummy_tx, &dummy_receive, 1);
...
dummy_tx = 0xA0;
 spi_send_recv(&SPI_MASTER_0, &dummy_tx, &i, 1);

But it would be more usual to just have an array of uint8_t types and send in a single command, unless the CAN device has issues with that.

RE: SPI master cannot receive SPI slave response

Susheel Nuguru — Thu, 03 May 2018 06:42:03 GMT

have you switched to another SPI module? it has been 2 months and i thought you might have figured out the issue.

RE: SPI master cannot receive SPI slave response

Ree Wang — Wed, 02 May 2018 22:54:41 GMT

Hi Renato,

Have not solved it yet... unfortunately

RE: SPI master cannot receive SPI slave response

RenatoMorelli — Wed, 02 May 2018 19:27:51 GMT

Hi Ree Wang 😃

Did you manage to solve this spi issue? I am facing something similar

RE: SPI master cannot receive SPI slave response

Ree Wang — Wed, 14 Mar 2018 00:11:51 GMT

Thanks. I use nRF52840 Preview DK, the SDK is nRF5 SDK v14.2.0. I don't have logic analyzer... I will check the points you mentioned.

RE: SPI master cannot receive SPI slave response

Susheel Nuguru — Tue, 13 Mar 2018 14:57:58 GMT

Which SDK version are you using and which nRF52 DK are you using? is it 0.10.0 or 0.11.0

SPI is very extensively used module, So I would be surprised if there are any unknown issues in it. That said.

Could you take a logic analyzer and compare the two outputs. There might be a deviation in the clocks? different initial values? or default pin pull configuration? hard to say, but logic analyzer should reveal it.

RE: SPI master cannot receive SPI slave response

Ree Wang — Fri, 09 Mar 2018 15:45:52 GMT

Thanks. I have tried all 4 modes. But no one can fix the issue...

RE: SPI master cannot receive SPI slave response

Susheel Nuguru — Fri, 09 Mar 2018 14:15:03 GMT

Looks like the SPI mode does not match with what the slave is expecting. Can you please double check the spec of the sensor with what mode it expects SPI data.