Read 18bits from SPI?

[bx]

Hi,

I'm using PCA10028 to communicate with ADS1131 (www.ti.com/.../ADS1131) which outputs 18bit on SPI bus. I managed to get the data out by reading 24bits, but it feels odd doing it this way. Also the SPI example works out the amount of data to be read by the length of data to be sent, and is "sending" data out even though the MOSI pin is configured as NRF_DRV_SPI_PIN_NOT_USED.

Everything kind of works for me, but I'd like to know if there's a more elegant way of doing this.

Best regards,

Borut

[Øyvind Karlsen]

Hi,

SPI normally uses entire bytes, so it makes sense to receive 8, 16 24, 32 bits etc in each section.

If everything is working for you I think it's better to follow the standard and focus on keeping your code well commented for easy review.

Best regards,

Øyvind

[awneil]

Err - the thing with SPI (unlike I2C, say) is that there is no standard for this stuff!

The only thing that SPI defines is the 4 wires - it says absolutely nothing about numbers of bits or anything else to do with higher-level protocols.

So the question is actually about the specific peripheral implementation in the particular chip (nRF51422) - and has nothing to do with SPI itself.

en.wikipedia.org/.../Serial_Peripheral_Interface_Bus