Add ICACHE_RAM_ATTR to __pinMode in core_esp8266_wiring_digital.c

[rolpal]

Basic Infos

It is known that random resets are caused by code in Interrupt service routine access flash program memory and most functions now have ICACHE_RAM_ATTR to prevent this but In file core_esp8266_wiring_digital.c the following function do not
extern void __pinMode(uint8_t pin, uint8_t mode)

Hardware

Hardware: ESP-01
Core Version: 2.3.0

Description

I need to alter pin mode while serving Interrupts since the few I/O pins available on the ESP-01 force me to use pins for dual purposes. Doing this require the use of pinMode() function that currently is not ISR safe (no ICACHE_RAM_ATTR).

Could the ICACHE_RAM_ATTR please be added to the pinMode function as well?
My current solution of modifying the library is obviously not preferred...

Settings in IDE

Not really in scope of problem but as below:

Module: Generic ESP8266 Module
Flash Size: 512K
CPU Frequency: 80Mhz
Flash Mode: DIO
Flash Frequency: 40Mhz
Upload Using: SERIAL
Reset Method: ck

Sketch

Only a snip of the ISR

void ICACHE_RAM_ATTR serve_interrupt() {
  noInterrupts();                              // disable further interrupts
  digitalWrite(_ok_out_pin, HIGH);    // indicate interrupt is served
  mill = millis();                         // get current value for millis()
  if ((mill - last_millis) > 2ul) {     // data interleave (bit interleave is only 1ms)
    number_of_bits = 0;              // new data set, reset bit counter
  }
  last_millis = mill;                     // time of last received bit (normally 1ms each)
  
  if (digitalRead(_ck_in_pin)){         // led slot
    digitalWrite(_out_pin, HIGH);     // free the bus for led signal from central
  } else {                                      // key slot
    if (key_out & 0x0001) {
      digitalWrite(_out_pin, LOW);    // send key bit if any
    } else {
      digitalWrite(_out_pin, HIGH);   // free the bus if no key bit to send
    }
    key_out = key_out >> 1;          // prepare for next key bit
  }

  pinMode(_alarm_in_pin,INPUT);      // Changed to be used for sensing alarm state

_ok_out_pin is the same as _alarm_in_pin

Debug Messages

N/A

[devyte]

@igrr what are your thought of this in view of #3579?

[igrr]

Yes, #3579 has to be implemented as a fix.

@rolpal if the issue is still relevant to you, then i suggest modifying the mode register of the GPIO directly in your ISR. Take a look at __pinMode implementation for details. This way you will get more free space in IRAM. I will close this issue, if you want to follow the progress, please follow the link to #3579 and click "Subscribe" button there.