Additional device for Espruino to support 8 pins in parallel (for discussion)

That's great!

Actual status, compared to direct_io branch is: switched fast io off (return false in jshGetPinAddress)

If you switched off fast IO, I believe you could just switch back to the master branch and forget about direct_io? All the other speed improvements are already pushed into master.

IMO direct_io would be great if we could get it working though.

how do we call task relevant RTOS function ? We could use #ifdef ESP32 or #ifdef RTOS. I would prefer the 2nd one.

There's actually already jshInterruptOn() and jshInterruptOff() - would those do what's needed, or is that overkill?

But yes, feel free to add an RTOS define to the Makefile and use #ifdef RTOS - I guess something like #ifdef FREERTOS may already exist?

do we need jshIsPinValid(d->pins[n]) in jswrap_io_shiftOutCallback ? Isn't this already done in jswrap_io_shiftOut ?

Yes, it's still needed. The check is only done when setting pin state.

The idea is you might be able to call it with pins = [D0,undefined,undefined,undefined,undefined,D1] if maybe you only wanted to use certain bits from the data you were sending. We could remove that functionality and make jswrap_io_shiftOut error if a pin couldn't be found though? That might be more sensible.

If you wanted to make it faster you could change the test to: d->pins[n] != PIN_UNDEFINED though?

In terms of speeding up IO, could you move gpio_matrix_out from jshPinSetValue into jshPinSetState? I think that should give you a bit extra:

https://github.com/espruino/Espruino/blob/master/targets/esp32/jshardware.c#L324