Nano R4 not interrupting?

Official Hardware Nano Family Nano R4
1

I have a square wave signal connected to pin D2 (INT0)on Nano. My code fires an interrupt servicing routine when that changes, and is reported within loop(). All this works just fine for every flavour of Nano that I have. In fact, every Arduino that I have … except Nano R4, which is new to me. I can see it is executing setup() just fine. But, for the Nano R4. It’s just not executing the interrupt servicing routine. Is there anything different about the R4? Seems to me it can’t be that interrupts are disabled because I know they are coming through on my other code. I know the D2 input is wiggling up and down from physical tests … and swapping Arduinos.

For your information, the signal that’s driving it is a GPS pulse per second line that goes high once per second and stays high for 100 milliseconds.

const byte PPS_PIN = 2;
const long MONITOR_BAUDRATE = 1000000;

volatile byte           g_bFresh;
volatile unsigned long  g_ulMicroSecs;

///////////////////////////////////////////////////////////////////////////////

void EdgeISR(){
  //Serial.print("*");
  if (g_bFresh == 0){
    g_ulMicroSecs = micros();
    if (digitalRead(PPS_PIN)) {
      g_bFresh = 1;
    } else {
      g_bFresh = 2;
    }
  }
}

///////////////////////////////////////////////////////////////////////////////

void setup() {
  Serial.begin(MONITOR_BAUDRATE);
  while(!Serial) delay(5);

  attachInterrupt(digitalPinToInterrupt(PPS_PIN), EdgeISR, CHANGE);
  pinMode(PPS_PIN, INPUT);
  g_bFresh = 0;
  g_ulMicroSecs = micros();
  Serial.println();
  Serial.print(g_bFresh);
  Serial.print(", ");
  Serial.print(g_ulMicroSecs);
  Serial.println(", Starting");
}

///////////////////////////////////////////////////////////////////////////////

void loop() {
  if (g_bFresh > 0) {
    Serial.print(g_bFresh);
    Serial.print(", ");
    Serial.println(g_ulMicroSecs);
    g_bFresh = 0;
  } else {
    Serial.print (".");
    delay(50);
  }
}

///////////////////////////////////////////////////////////////////////////////
2

At the bottom of your topic are related topics... This incomplete topic addresses R4 interrupts: How to use Arduino UNO R4 interrupt

3

I'm not clear about the Resesas core, and what is being configured with attachInterrupt( ) and pinMode( ) but for the R4 pinMode( ) needs to be set before attachInterrupt( ).

pinMode(PPS_PIN, INPUT);
  attachInterrupt(digitalPinToInterrupt(PPS_PIN), EdgeISR, CHANGE);
  //pinMode(PPS_PIN, INPUT);
4

Indeed.

Results of applying @cattledog's fix with a 1Hz signal applied to pin 2 of an R4 Nano:

0, 2489903, Starting
.........1, 2897898
..........2, 3397832
..........1, 3897765
..........2, 4397700
..........1, 4897633
..........2, 5397567
..........1, 5897499
..........2, 6397457
.........1, 6897368
..........2, 7397300
..........1, 7897235
..........2, 8397168
5

Great feedback. Thank you @cattledog for proposing the solution. Thank you @van_der_decken for demonstrating success. “As ever”, the answer was where I wasn’t looking. I say as ever because I feel I should have been looking there, and I wasn’t. I had read that, by default, on startup, the pin is configured as an input, so I could digitalRead() the pin & it would reflect the signal being presented. I had added in the pinMode() without real justification in the vain hope that it might have some effect. I can’t say where I had read this, but @cattledog had exposed something I had not read, or had overlooked. With the enormous amount of information available, this is far from the first time that I have missed the key point. That’s where this forum pays dividends - in spades!

If anyone is interested, the following is a snapshot of the monitor output for my GPS test program.

31986,0.00,0,379,1,$GNRMC,090854.500,A,5051.1477,N,00100.4950,W,0.10,220.19,200326,,,A*66
32086,0.00,0,380,1,$GNRMC,090854.600,A,5051.1474,N,00100.4949,W,0.08,220.19,200326,,,A*67
32184,0.00,0,381,1,$GNRMC,090854.700,A,5051.1470,N,00100.4949,W,0.08,220.19,200326,,,A*62
32286,0.00,0,382,1,$GNRMC,090854.800,A,5051.1467,N,00100.4948,W,0.07,220.19,200326,,,A*65
32386,0.00,0,383,1,$GNGGA,090854.900,5051.1464,N,00100.4948,W,1,6,3.07,1.2,M,47.3,M,,*5E
32392,0.00,0,384,1,$GNRMC,090854.900,A,5051.1464,N,00100.4948,W,0.06,220.19,200326,,,A*66
     32411,     32411,  32411051, 999974, 99996, PPS
32494,0.00,0,385,1,$GNRMC,090855.000,A,5051.1462,N,00100.4947,W,0.06,220.19,200326,,,A*67
32590,0.00,0,386,1,$GNRMC,090855.100,A,5051.1459,N,00100.4947,W,0.05,220.19,200326,,,A*6D
32688,0.00,0,387,1,$GNRMC,090855.200,A,5051.1456,N,00100.4946,W,0.04,220.19,200326,,,A*61
32785,0.00,0,388,1,$GNRMC,090855.300,A,5051.1454,N,00100.4946,W,0.03,220.19,200326,,,A*65
32884,0.00,0,389,1,$GNGGA,090855.400,5051.1451,N,00100.4945,W,1,6,3.07,1.4,M,47.3,M,,*5F
32890,0.00,0,390,1,$GNRMC,090855.400,A,5051.1451,N,00100.4945,W,0.03,220.19,200326,,,A*64
32984,0.00,0,391,1,$GNRMC,090855.500,A,5051.1449,N,00100.4945,W,0.03,220.19,200326,,,A*6C
33085,0.00,0,392,1,$GNRMC,090855.600,A,5051.1446,N,00100.4945,W,0.03,220.19,200326,,,A*60
33184,0.00,0,393,1,$GNRMC,090855.700,A,5051.1444,N,00100.4945,W,0.03,220.19,200326,,,A*63
33285,0.00,0,394,1,$GNRMC,090855.800,A,5051.1442,N,00100.4945,W,0.04,220.19,200326,,,A*6D
33387,0.00,0,395,1,$GNGGA,090855.900,5051.1440,N,00100.4945,W,1,6,3.07,1.5,M,47.3,M,,*53
33393,0.00,0,396,1,$GNRMC,090855.900,A,5051.1440,N,00100.4945,W,0.04,220.19,200326,,,A*6E
     33411,     33411,  33411023, 999972, 99996, PPS
33485,0.00,0,397,1,$GNRMC,090856.000,A,5051.1438,N,00100.4945,W,0.04,220.19,200326,,,A*6B
33587,0.00,0,398,1,$GNRMC,090856.100,A,5051.1436,N,00100.4945,W,0.03,220.19,200326,,,A*63
33685,0.00,0,399,1,$GNRMC,090856.200,A,5051.1435,N,00100.4944,W,0.03,220.19,200326,,,A*62
33784,0.00,0,400,1,$GNRMC,090856.300,A,5051.1433,N,00100.4944,W,0.04,220.19,200326,,,A*62
33885,0.00,0,401,1,$GNGGA,090856.400,5051.1432,N,00100.4944,W,1,6,3.07,1.5,M,47.3,M,,*59
33891,0.00,0,402,1,$GNRMC,090856.400,A,5051.1432,N,00100.4944,W,0.05,220.19,200326,,,A*65
33984,0.00,0,403,1,$GNRMC,090856.500,A,5051.1430,N,00100.4945,W,0.07,220.19,200326,,,A*65
34084,0.00,0,404,1,$GNRMC,090856.600,A,5051.1429,N,00100.4945,W,0.08,220.19,200326,,,A*61
34184,0.00,0,405,1,$GNRMC,090856.700,A,5051.1427,N,00100.4945,W,0.10,220.19,200326,,,A*67
34284,0.00,0,406,1,$GNRMC,090856.800,A,5051.1425,N,00100.4945,W,0.12,220.19,200326,,,A*68
34384,0.00,0,407,1,$GNGGA,090856.900,5051.1424,N,00100.4945,W,1,6,3.07,1.5,M,47.3,M,,*52
34390,0.00,0,408,1,$GNRMC,090856.900,A,5051.1424,N,00100.4945,W,0.13,220.19,200326,,,A*69
     34411,     34410,  34410993, 999970, 99995, PPS
34486,0.00,0,409,1,$GNRMC,090857.000,A,5051.1422,N,00100.4946,W,0.14,220.19,200326,,,A*63
34586,0.00,0,410,1,$GNRMC,090857.100,A,5051.1425,N,00100.4946,W,0.15,220.19,200326,,,A*64
34685,0.00,0,411,1,$GNRMC,090857.200,A,5051.1427,N,00100.4946,W,0.15,220.19,200326,,,A*65
34785,0.00,0,412,1,$GNRMC,090857.300,A,5051.1430,N,00100.4947,W,0.14,220.19,200326,,,A*62
34885,0.00,0,413,1,$GNGGA,090857.400,5051.1432,N,00100.4947,W,1,6,3.07,1.4,M,47.3,M,,*5A
34891,0.00,0,414,1,$GNRMC,090857.400,A,5051.1432,N,00100.4947,W,0.14,220.19,200326,,,A*67