Data type error when changing array contents for CAN messages

[rsw015]

I'm writing a device configuration script using CAN. I have written other CAN scripts using arrays to store desired message data. Up until now, I haven't needed to overwrite this data.

One particular device has an extraordinarily large number of messages needing to be sent. Many of these messages follow a pattern in the data field, so, I'm attempting to iterate through these messages where possible.

My approach is to update a single array location with each iteration.

This one line of code is giving me problems:

      payload2[0] = x;

I'm getting this error:

Compilation error: incompatible types in assignment of 'unsigned char' to 'unsigned char [2]'

Could someone please help me either make this work or suggest an alternative solution?

This code is stripped down:

#include <Arduino_CAN.h>

void setup() {
  Serial.begin(9600);
  while (!Serial) { }

  if (!CAN.begin(CanBitRate::BR_250k))
  {
    Serial.println("CAN.begin(...) failed.");
    for (;;) {}
  }
  Serial.println("ready");
}

unsigned char payload2[1][2] = {0x00,0x41};
unsigned char *payload = payload2[0];
uint32_t CAN_ID = 0;
uint8_t hold2 = 0x5F;                                 //variable for new node IDs

void loop() {
hold2 = 0x60;
M01();
}

void M01(){
  unsigned char x = 0;
  CAN_ID=0x51;
  sNS2(0);
    for(int i = 0; i<=253; i++){
      x = i;
      Serial.println(x, HEX);
      payload2[0] = x;
      payload = payload2[0];
      sNS2(0);
    }
  while(1);
}

void sNS2(char p){                                                     //Sort-N-Send for an 2 databyte message,
  int rc = 0;
  if(sizeof(CAN_ID)==4){
    CanMsg msg(CanExtendedId(CAN_ID), sizeof(payload2[p]), payload);   //for CAN_ID, write CanExtendedID(CAN_ID) or CanStandardID(CAN_ID)
    rc = CAN.write(msg);
    Serial.println(msg);
  }else{
    CanMsg msg(CanStandardId(CAN_ID), sizeof(payload2[p]), payload);   //for CAN_ID, write CanExtendedID(CAN_ID) or CanStandardID(CAN_ID)
    rc = CAN.write(msg);
  }
}

[UKHeliBob]

unsigned char payload2[1][2] = {0x00,0x41};

Why has this array got 2 dimensions ?

[rsw015]

This is a stripped down code. There are more parts to the array used elsewhere, but not in this part of the code.

[UKHeliBob]

Bearing in mind that payload2 is a 2 dimensional array, when you do this

payload = payload2[0];

what do you expect payload to contain after this assignment ?

[rsw015]

Well now that you pointed that out, I think I understand the problem.

This does what I want. Thanks!

      payload2[0][0] = x;

[rsw015]

This was the desired output.

[UKHeliBob]

That's good !