How many max SPI slave sensor I can connect with Nrf52840 via SPIM

[Chitrang Talaviya]

Hello Folks,

I am using PCA 10056 Eval board. I am using SPIM0 to connect 5 slave sensors. The Chip select is done by the UART Tx pin. So If I send 0x01 over UARt then the sensor- 1 will be selected.

UART Tx byte -- Sensor 0x01 -- 1 0x02 -- 2 etc

Sensors are LSM6DSL

I have five sensors connected via SPIM0 to nordic nrf52840. I am only able to get the reading from 1 or 2 sensors only which is connected closely to nordic. Is there any max limit with the current SPIM hardware and software limitations in terms of max slaves?

ALso, How to change the CS duration and RX delay timing of the SPIM hardware using the SDK 14?

Thank you

[Chitrang Talaviya]

HEllo Dave, thank you for the answer. I am using the UART Tx as my chip select. I am not using any GPIOs as chip select. It is something like addressing kind of mechanism. I am using the Silego chip that reads the UART stream and assert a CS pin for that sensor. If you send 0x01 over UART TX then first sensor will be activated and so on. If you send any 0x00 over UART then that sensor will be de-selected