Error with attachInterrupt on a Wemos D1 mini

[jjedlicka]

Hi all, First I'll admit I a huge noob with coding. But I'm trying to program a Wemos D1 mini to act as a flow meter. The program I've written complies fine, but when it gets uploaded the light on the D1 flashes constantly and in the Serial I get the following error:

ets Jan 8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 3584, room 16
tail 0
chksum 0xb0
csum 0xb0
v2843a5ac
~ld

I've narrowed the problem down to the attachInterrupt line, but can't figure out whats wrong with it. Every example online I've found has something similar.

Here's my code:

#define BLYNK_PRINT Serial

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

char AUTH[] = "*****";
char WIFI_SSID[] = "*****";
char WIFI_PASS[] = "*****";

int flowPin;
int flowRate; 
int count=1; 

void setup() {
  flowPin = 4;
  pinMode(flowPin, INPUT);
  attachInterrupt(digitalPinToInterrupt(4), Flow, RISING);
  Serial.begin(115200);
  delay(1000);
  Serial.print("Connecting to: ");
  Serial.print(WIFI_SSID);

  WiFi.begin(WIFI_SSID, WIFI_PASS);
  int wifi_ctr = 0;
  while (WiFi.status() != WL_CONNECTED) {
    delay(5000);
    Serial.print("-");
  }

  Serial.println("WiFi Connected");

  Blynk.begin(AUTH, WIFI_SSID, WIFI_PASS);
  
}

void loop() {
  Blynk.run();

  count = 0;
  interrupts();
  delay(1000);
  noInterrupts();

  flowRate = (count * 2.25);
  flowRate = (flowRate * 60);
  flowRate = (flowRate / 1000);

  Serial.println(flowRate);
  Serial.print("L/Min");
  Blynk.virtualWrite(V1, flowRate);

}

void Flow() {
  count++;
}

[guix]

Hello,

Declare count as volatile :
volatile int count=1;

And add the attribute ICACHE_RAM_ATTR to the ISR :
void ICACHE_RAM_ATTR Flow() {

[sterretje]

You can add [code] before your code and [/code] after your code.

[jjedlicka]

You're a life saver! Thanks a lot, that worked.

It did error out on me though when I added the ICACHE_RAM_ATTR to the ISR. Instead it worked when I declared:
void ICACHE_RAM_ATTR Flow();
before void setup()

[RayLivingston]

The ISR MUST be defined before the attachInterrupt call. Instead of adding the ISR prototype, you can simply move the ISR above setup().