2 Replies Latest reply on Mar 22, 2019 2:19 AM by GaRo_3769926

    SPI Transfer separation: how does it work exactly?

    GaRo_3769926

      Good afternoon to whomever may be reading this, thank you for your time

       

      I'm currently developing a sensor with a PRoCBLE chip (CYBL10162-56LQXI), and I require an SPI communication between the PRoC chip and a BME280 sensor. It's 4-cable SPI.

       

      My problem is that the sensor requires me to read several bytes in a row without rising the CSB (SS0) signal. I've found that, in the SCB block configured as SPI Master (the way I want it) in PSoC Creator 4.2, there is an option for "Transfer separation", which is apparently what I want. The thing is that the documentation is lacking in this regard and I can't find exactly how it works, whether it only works for read+write or only for writing...

      SPI_BME280_Read.PNG

      This picture schematically represents what I want to do with a multiple-byte read: 1st, it lowers CSB (SS), then PSoC sends through MOSI a byte commanding to read a specific register, then reads a byte, and then reads another one without changing the CSB (SS) signal at all until the end of the reading. Is this possible to do with the PSoC functions as they are, or will I have to bitbang the CSB (SS) signal? Is the "Transfer separation" option just what I need, or does it only work for writing?

       

      Thank you in advance

      Gabriel