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]

Sorry from My side I am not able to explain my problem. I am not using UART to talk to the sensor. My sensor hardware has two chips one is LSM6DSL and SLG46536V. The SLG46536V is acting as a UART to GPIO converter. So if u send 0x01 over UART to SLG46536V, it will make one of the pins of SLG46536V to low and if you send 0x00 then it will make that pin high. So the output pin1 of the SLG46536V is connected to sensor 1. output pin2 of SLG46536V is connected to sensor2 and so on. We have max seven sensors. So all the sensor hardwares are having this one SLG46536V and one LSM sensor. We are using SLG46536Vso that we do not need to use GPIOs of the controller.