Nano A0 conflicts with D10,D11

Projects Programming
1

I am writing a program to read data strings from a Win10 program, convert the strings to a specified frequency and use to set a octal latching buffer (74LS373) that will replicate a radio keypad entry. I am using digital pins 10, 11 with Serial Software library to a USB Serial comm to the PC program. I want to use analog pins A0-A7 to set the latching octal buffer outputs but when I compile, my Serial D10,D11 doesn't work at all. I can set A1-A7 and all is good but as soon as set A0. Nothing works. Is there some Nano conflict between A0 and digital pins 10 or 11?

void setup() {
Serial.begin(57600);
mySerial.begin(9600);

pinMode(A0, OUTPUT);
pinMode(A1, OUTPUT);
pinMode(A2, OUTPUT);
pinMode(A3, OUTPUT);
pinMode(A4, OUTPUT);
pinMode(A5, OUTPUT);
pinMode(A6, OUTPUT);
pinMode(A7, OUTPUT);

Serial.println("");
Serial.println("");
}

void loop() {
recvUntilEndMarker();
ProcessNewData();
}

2

Just to be sure, when you say "Nano", do you mean the original Nano with the ATmega328P, or one of the new Nano boards (Nano Every, Nano 33 IoT, Nano 33 BLE, Nano 33 BLE Sense)?

It also may well be helpful if you post your full sketch, rather than the snippet. Please use code tags (</> button on the toolbar), not the quote tags. If the sketch is longer than the 9000 character maximum imposed by the forum software, you can add it as an attachment (click the "Reply" button for an attachments option.

3

pinMode(A6, OUTPUT);
pinMode(A7, OUTPUT);

On the ATmega328 nanos, A6 and A7 can not be outputs.

4

westfw:
On the ATmega328 nanos, A6 and A7 can not be outputs.

Thank you. Is there a reference source for all Arduino's that lists these differences between boards?

My Nano is generic ATmega328P and I could not get it to upload with standard 328P only the "Old Bootloader" would work.

Here is my code

#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11);
const byte numChars = 16;
char receivedChars[numChars];   // an array to store the received data
char instructionRcvd[numChars]; // an array to store complete instruction set for processing
boolean newData = false;
boolean instructProcessed = false;
String stringOne; //will be used for string comparisons


void setup() {
  Serial.begin(57600);
  mySerial.begin(9600);
  pinMode(A0, OUTPUT);
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);
  pinMode(A3, OUTPUT);
  pinMode(A4, OUTPUT);
  pinMode(A5, OUTPUT);
  pinMode(A6, OUTPUT);
  //pinMode(A7, OUTPUT);

  /*
    pinMode(7, OUTPUT);
    digitalWrite(7, LOW);   // to Latch 74LS373 set HIGH

    digitalWrite(A0, LOW);
    digitalWrite(A1, LOW);
    digitalWrite(A2, LOW);
    digitalWrite(A3, LOW);
    digitalWrite(A4, LOW);
    digitalWrite(A5, LOW);
    digitalWrite(A6, LOW);
    digitalWrite(A7, LOW);
  */
  Serial.println("<Arduino is ready>");
  Serial.println("<Sending PC is ready>");
}

void loop() {
  recvUntilEndMarker();
  ProcessNewData();
}

void recvUntilEndMarker() {
  static byte ndx = 0;
  char endMarker = ';';
  char rc;

  while (mySerial.available() > 0 && newData == false) {
    rc = mySerial.read();  // PC is sending a random series of two character letters ending with a ";"
    if (rc != endMarker) {
      receivedChars[ndx] = rc;
      ndx++;
    }
    else if (rc == endMarker) {
      receivedChars[ndx] = rc;  //add endMarker
      receivedChars[ndx + 1] = '\0'; // then terminate the string
      ndx = 0;
      strcpy(instructionRcvd, receivedChars);
      Serial.println(instructionRcvd);
      //RESET receiveChars to ALL NULLS
      for (int i = 0; i < sizeof(receivedChars);  ++i ) receivedChars[i] = '\0';
      newData = true;
      instructProcessed = false;
    }
  }
}
5

Is there a reference source for all Arduino's that lists these differences between boards?

Such a document would be very difficult/impossible to create. You would be better off looking for the specification of the board that you want to use or the function that you want to use

digitalWrite()

The analog input pins can be used as digital pins, referred to as A0, A1, etc. The exception is the Arduino Nano, Pro Mini, and Mini’s A6 and A7 pins, which can only be used as analog inputs.