Nicla Sense ME connect external device via SPI

[RobP]

Hello,

I am trying to connect my Nicla Sense ME with an additional external device through SPI. However using the SPI minimal example as found on the cheat sheet it seems there is only silence when monitoring the GPIO logic levels of CS, CIPO, COPI or SCLK with an Oszi. What am I missing?

Thank you & Regards,

Rob

#include <SPI.h>
#include "Nicla_System.h"

#define EPD_CS p29

void setup() {
nicla::begin(); // initialise library
nicla::leds.begin(); // Start I2C connection
SPI.begin();
}

void loop() {
nicla::leds.setColor(green); //turn green LED on
delay(1000); //wait 1 second
nicla::leds.setColor(off); //turn all LEDs off
delay(1000); //wait 1 second

digitalWrite(EPD_CS, LOW); //pull down the CS pin
SPI.transfer(0x00); // address for device, for example 0x00
SPI.transfer(0x01); // value to write
digitalWrite(EPD_CS, HIGH); // pull up the CS pin
}

[BSTRobin]

Hi RobP,

Do you mean you haven't captured any hardware signal after you run SPI example code?

[RobP]

Exactly, I cant see any SPI hardware signal until now. Expected some activity on CLK signal pin (p11) and COPI (p27) every 2 seconds but no luck yet.

[RobP]

I am still not able to establish an SPI connection from nRF to an external SPI slave device. The described SPI pins showing no signal. It would be great to get a hint what’s wrong with the minimal code shown above.

[RobP]

After changing the LDO for VDDIO_EXT from 3.3V to 1.8V...

nicla::disableLDO();
nicla::enable1V8LDO();

 ... the good news is that I can see now the CS pin working fine (Ch1/yellow):

For some reason this does not work with 3.3V setting for VDDIO_EXT (which is the default setting if I got it right).

The other pins SCLK, COPI and CIPO still show now signal.