serialWrite does not appear to work

daftfox commented 5 years ago

I have been breaking my head over this for quite some time am unable to figure out what the problem could be.

I'm developing a TypeScript application to control multiple firmata compatible devices over WiFi or the serial interface. One of the use-cases I have requires me to send data from a microcontroller to a secondary device connected over UART. The serialWrite method should be perfect for this, were it not that I don't see anything happening on the TX or RX lines. Not with an arduino uno running the default serialpassthrough sketch and not even when hooked up to an oscilloscope. The device I am using is the ESP8266 (Wemos D1).

code is as follows:

const serialOptions = {
    portId: firmata.SERIAL_PORT_IDs.SW_SERIAL0,
    baud: 9600,
    rxPin: 4,
    txPin: 5
};

firmata.serialConfig( serialOptions );
firmata.serialWrite( firmata.SERIAL_PORT_IDs.SW_SERIAL0, [0x01, 0x03, 0x03, 0x07] );

I'm running the code above after the 'ready' event has been emitted by firmatajs. The device is currently connected over WiFi.

I have flashed configurable firmata with support for serial connection to the device in question. Would anyone be able to help me out? I'm kinda at a loss here.

soundanalogous commented 5 years ago

Are you able to run a simple blink application to ensure the issue is with serialWrite and not with the wifi connection to the board?

soundanalogous commented 5 years ago

Ah, software serial is not currently supported for the ESP8266. You may be able to use HW_SERIAL1 if the board is configured to enable UART1. Otherwise, it looks like ESP8266 has a software serial implementation so it may be possible to add another condition here to include the proper software serial library for an ESP8266. If you try that and it works, please submit a pull request.

daftfox commented 5 years ago

@soundanalogous thanks for the quick reply. Pretty much everything seems to work, except for the serialWrite method. Haven't tried out the serialRead yet, but I figured I'll burn that bridge when I get there.

I'll try out your suggestion and add an extra condition to the serialFirmata.h dependency. I'll keep you updated when I know more.

daftfox commented 5 years ago

Hey, that did the trick! I was a little confused about not seeing anything show up in the serial monitor, but that was because I wasn't sending bytecodes corresponding with ascii characters. I will submit a pull request.

soundanalogous commented 5 years ago

This has been fixed in the Firmata repo: https://github.com/firmata/arduino/pull/420.

firmata / firmata.js

serialWrite does not appear to work #196