How do I port C++ code to Esp8266 and Esp32 using interrupts from code written for older boards - c++

Question

I am trying to port some C++ Arduino code to more recent ESP8266 and ESP32 boards.
I have checked already the Arduino Stack Exchange forum unfortunately without results
Porting this C++ code from older Arduino to Esp8266/Esp32 does not work, I have added also the compiling errors at the bottom of this question:
/* rcTiming.ino -- JW, 30 November 2015 --
* Uses pin-change interrupts on A0-A4 to time RC pulses
*
* Ref: https://arduino.stackexchange.com/questions/18183/read-rc-receiver-channels-using-interrupt-instead-of-pulsein
*
*/
#include <Streaming.h>
static byte rcOld; // Prev. states of inputs
volatile unsigned long rcRises[4]; // times of prev. rising edges
volatile unsigned long rcTimes[4]; // recent pulse lengths
volatile unsigned int rcChange=0; // Change-counter
// Be sure to call setup_rcTiming() from setup()
void setup_rcTiming() {
rcOld = 0;
pinMode(A0, INPUT); // pin 14, A0, PC0, for pin-change interrupt
pinMode(A1, INPUT); // pin 15, A1, PC1, for pin-change interrupt
pinMode(A2, INPUT);
pinMode(A3, INPUT);
PCMSK1 |= 0x0F; // Four-bit mask for four channels
PCIFR |= 0x02; // clear pin-change interrupts if any
PCICR |= 0x02; // enable pin-change interrupts
}
// Define the service routine for PCI vector 1
ISR(PCINT1_vect) {
byte rcNew = PINC & 15; // Get low 4 bits, A0-A3
byte changes = rcNew^rcOld; // Notice changed bits
byte channel = 0;
unsigned long now = micros(); // micros() is ok in int routine
while (changes) {
if ((changes & 1)) { // Did current channel change?
if ((rcNew & (1<<channel))) { // Check rising edge
rcRises[channel] = now; // Is rising edge
} else { // Is falling edge
rcTimes[channel] = now-rcRises[channel];
}
}
changes >>= 1; // shift out the done bit
++channel;
++rcChange;
}
rcOld = rcNew; // Save new state
}
void setup() {
Serial.begin(115200);
Serial.println("Starting RC Timing Test");
setup_rcTiming();
}
void loop() {
unsigned long rcT[4]; // copy of recent pulse lengths
unsigned int rcN;
if (rcChange) {
// Data is subject to races if interrupted, so off interrupts
cli(); // Disable interrupts
rcN = rcChange;
rcChange = 0; // Zero the change counter
rcT[0] = rcTimes[0];
rcT[1] = rcTimes[1];
rcT[2] = rcTimes[2];
rcT[3] = rcTimes[3];
sei(); // reenable interrupts
Serial << "t=" << millis() << " " << rcT[0] << " " << rcT[1]
<< " " << rcT[2] << " " << rcT[3] << " " << rcN << endl;
}
sei(); // reenable interrupts
}
The compiling error is:
expected constructor, destructor, or type conversion before '(' token
at line:
ISR(PCINT1_vect) {
I am seeking suggestions to get it working thank you.

Answer 1

All ESP32 GPIO pins are interrupt-capable pins.
You can use interrupts, but in a different way.
attachInterrupt(GPIOPin, ISR, Mode);
Mode – Defines when the interrupt should be triggered. Five constants are predefined as valid values:HIGH, LOW, CHANGE, RISING, FALLING
void IRAM_ATTR ISR() {
Statements;
}
Interrupt service routines should have the IRAM_ATTR attribute, according to the ESP32 documentation