SD card and NRF24l01 problem

Using Arduino Project Guidance
1

Hello

I have the following set-up:

An Arduino pro mini with a NRF24l01 module incorporated - one of these
https://www.electrodragon.com/product/nrf24duino-arduino-mini-plus-nrf24l01-board/

Attached to this is an SD card reader on pins 10-13 (pin 10 as CS)
Also attached to this is an OLED display (this is not currently in use though it does work)
I have a 100uf capacitor across the supply to the ATMEGA (across the regulated 3.3V not the VIN)
All this connected to the PC with a FDTI board.

Running the following simple code (adapted originally from Robin2's sample sketch):

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
#include <SD.h>

byte currentcard [13];


File myFile;
const int chipSelect = 10;

#define CE_PIN   7
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R', 'x', 'A', 'A', 'A'};

RF24 radio(CE_PIN, CSN_PIN);

byte dataReceived[13]; // this must match dataToSend in the TX
bool newData = false;

//===========

void setup() {
  Serial.begin(9600);
  pinMode(SS, OUTPUT);
  delay(200);

  if (!SD.begin(chipSelect)) {
    Serial.println("card initialization failed!");
    return;
  }
  Serial.println("card initialization done.");
  

  Serial.println("SimpleRx Starting");
  radio.begin();
  radio.setDataRate( RF24_250KBPS );
  radio.openReadingPipe(1, thisSlaveAddress);
  radio.startListening();
}

//=============

void loop() {


  if ( radio.available() ) {
    radio.read( &currentcard, sizeof(currentcard) );
    newData = true;

    for (int i = 0; i < 13; i++) Serial.println (currentcard[i]);

  }

}

Problem: so long as the card reader is connected, the nrf24l01 does not receive (or at least, hardly ever). If I disconnect the card reader, it works. The card reader itself works (if it is connected, it will initialise and read/write cards).

As stated, I've included the often-recommended capacitor even though I have never needed it to work before with this module.

I did wonder if there was a power supply issue. The card reader seems to be drawing about 7mA which doesn't seem a great deal.

Any ideas please, or more information needed?

2 
const int chipSelect = 10;

#define CE_PIN   7
#define CSN_PIN 10

You are using pin 10 for 2 different things. Recommend using pin 4 (if available) for the SD chip select.

Some SD card modules will not play well with other devices on the SPI bus. The problem is with the way the level shifter on the SD module is wired. The ones that do not work well have the MISO signal running through the level shifter. That causes the MISO signal to not be released so that the other devices can control it. The modules made by Adafruit (and some others) have the MISO signal going from the SD card straight to the MISO, bypassing the level shifter. Look at the schematic for the Adafruit module to see what to look for. DO (data out) is the MISO signal.

3

[slaps head!] yes, thank you