Not able to get serial data from ads1293 sensor using nRF52833

RE: Not able to get serial data from ads1293 sensor using nRF52833

Turbo J — Tue, 17 Mar 2026 14:23:39 GMT

MOSI misconfigured or otherwise in use on the DK. Try a different pin. Note that there are quite a few connected to other hardware and should not be used externally.

RE: Not able to get serial data from ads1293 sensor using nRF52833

Suryalakshmi — Tue, 17 Mar 2026 10:24:19 GMT

I was talking about the nRF52833 DK. I used oscilloscope but both MOSI and MISO are flat. I am trying to find out why it's happening.

RE: Not able to get serial data from ads1293 sensor using nRF52833

Turbo J — Tue, 17 Mar 2026 07:46:01 GMT

What NRF52833 board are you talking about? The DK is set up correctly when you can flash and debug your code.

No idea why your SPI communication fails - you will need to use some kind of oscilloscope or logic analyser (LA) here. I still suspect that the TI ADS chip just refuses to talk to you at all.

RE: Not able to get serial data from ads1293 sensor using nRF52833

Suryalakshmi — Tue, 17 Mar 2026 06:42:01 GMT

I tried so much. Still no impovement. Now I suspect whether if it is a software issue. There are many deep switches in the nrf52833 board. What should be there status? Currently the way I have kept them allows me to connect to J link and flash codes in my board. Does the configuration changes or something during SPI communication?

RE: Not able to get serial data from ads1293 sensor using nRF52833

hmolesworth — Mon, 16 Mar 2026 17:20:19 GMT

If you see nothing on MOSI, perhaps try adding:

   nrf_gpio_pin_set(MOSI_PIN);
   nrf_gpio_cfg_output(MOSI_PIN);

SPI transfers data in via MISO every clock cycle, so when sending a command byte and receiving a data byte 16 clock cycles are used and so 2 bytes are received with the required data in the 2nd byte, not the first.

Try changing to 2-byte receive, something like this:

uint8_t spi_transfer(uint8_t data)
{
  uint8_t rx[2];
  APP_ERROR_CHECK(
    nrf_drv_spi_transfer(&spi, &data, 1, &rx, 2)
  );
  return rx[1];
}

Also not sure but the ADS1293 might require a command to start the clock

RE: Not able to get serial data from ads1293 sensor using nRF52833

Suryalakshmi — Mon, 16 Mar 2026 12:26:50 GMT

I changed CS pin from P0.11 To P0.13. But it didn't made any changes. Still SPI is not communicating

RE: Not able to get serial data from ads1293 sensor using nRF52833

Suryalakshmi — Mon, 16 Mar 2026 12:17:07 GMT

The SCK is having signal but MISO and MOSI are both flat when I checked with oscilloscope. What will be the main difference if I switch to NCS SDK.

RE: Not able to get serial data from ads1293 sensor using nRF52833

Kazi Afroza Sultana — Mon, 16 Mar 2026 10:33:34 GMT

Hello,

Pin P0.12 and P0.11 are used for trace buffer pin also. You have ECG project, You are not actively using trace but debugger may automatically enable it during debug session, that can potentially interfere with the SPI CS signal. You can try to use another available pin for CS?

Thanks.

Kazi

RE: Not able to get serial data from ads1293 sensor using nRF52833

Turbo J — Mon, 16 Mar 2026 06:44:27 GMT

My general recommendation with these ADCs is: Check all of the basics. That is both analog and digital supply voltages and the pin config for the clock. Rev ID all zeros means the chip won't bother talking to you at all.

Otherwise: Oscilloscope.

Oh, and swich your code over to NCS SDK. Code looks like its still on the old unsuported stuff.

RE: Not able to get serial data from ads1293 sensor using nRF52833

Suryalakshmi — Mon, 16 Mar 2026 06:27:04 GMT

Actually the PCB works at 3.3V. It uses logic level shifter for Arduino.

RE: Not able to get serial data from ads1293 sensor using nRF52833

Turbo J — Mon, 16 Mar 2026 06:24:39 GMT

If that PCB was set up for the 5V arduino UNO, its not compatible with any NRF5xxxx MCU chip. Those are NOT 5V tolerant.