How do I specify my register address for SPI driver interface?

RE: How do I specify my register address for SPI driver interface?

Jørgen Holmefjord — Tue, 22 Aug 2017 06:32:03 GMT

Yes, that should work. Note that for reads, you might have to increase the bytesNumberRx, as reading of usefull data will not start until after the first write, but the read buffer will start filling when writing starts.

RE: How do I specify my register address for SPI driver interface?

ndarkness — Mon, 21 Aug 2017 11:32:32 GMT

So for writting something like this APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi_BMI160, slaveDeviceId,sizeof(slaveDeviceId), NULL, 0)); Or I should do two writings? `

RE: How do I specify my register address for SPI driver interface?

ndarkness — Mon, 21 Aug 2017 11:26:46 GMT

My sensor hasn't arrived yet, so it is hard to test :S In case of the write function, I should set the read buffer as well?

RE: How do I specify my register address for SPI driver interface?

Jørgen Holmefjord — Mon, 21 Aug 2017 10:56:42 GMT

Yes, something like that should work. Have you tested it?

RE: How do I specify my register address for SPI driver interface?

ndarkness — Mon, 21 Aug 2017 10:41:05 GMT

Hi Jorgen thanks for replying, if the use the call like this. THen first I have to write which register I want to read? I think that it is that you address the register to read and perform a reading from it, am I wrong? Thus I would have to make a call to nrf_driver_spi_transfer specifying the register to be written, like this APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi_BMI160, &reg_addr, 1, rxData, bytesNumberRx)); right?

RE: How do I specify my register address for SPI driver interface?

Jørgen Holmefjord — Mon, 21 Aug 2017 10:29:07 GMT

Hi,

This should be documented in the datasheet of your device. Typically, the first byte transferred is the register address. You have not defined any TX buffer in the call to nrf_drv_spi_transfer, so you will not be able to write anything to the device.

Best regards,

Jørgen