Serial connector on the next revision ?

[olivier.jan]

Hi,
With new PCs and Macs having less and less RS-232 I was wondering if it would be possible to add a connector for Serial on the motherboard.
This will make usage of simple and cheap FTDI232 serial<->USB adapters for debugging with dial cart or other tools.
Anyway, we can always piggy-back on Max238 or MFP pins, but it might not be as reliable.

[exxos]

It has a connector for serial on the board just like all other ST's do... ?

EDIT:
Or do you mean add a header for serial ? If that's the case someone would have to try those USB to serial adapters first as I never had any luck with them in the past.

[olivier.jan]

Yes, sorry, I meant a header placed before the Max238 in order to use simple TTL serial without all the voltage conversions.
Doing so, you could have a simple USB connection on the motherboard for serial operations.
I will try it (plugging on Max238) once I get a diagnosis cart and let you know if it works properly.

[exxos]

Yeah it could be added, though not sure if there is room off-hand..

If you are going to try it, might be easier to just wire to a RS232 plug.. or remove the port and just bodge wire to the port on the MB.. be easier than trying to solder wires to the MAX IC.

[olivier.jan]

Actually it must be connected before the Max238 ( so on mfp, on the Max or somewhere between) where the signals are still 0-5v. After the Max, we’re on rs232, so negative voltage for 0 and positive for 1 and it might fry the serial<-> USB adapter.
But I’ll try with clips first before trying any soldering.

[olivier.jan]

I finally tested the FTDI on a STFM motherboard (not on the H5, but it should work the same), it’s very convenient.
Just plugged RX, TX and ground to SO,SI on MFP and GND on Motherboard, got access to the serial immediately.

IMG_0150.JPG

IMG_0149.JPG

IMG_0148.JPG

And even if my soldering skills are pretty low, the GLUE mess is not mine :)

[exxos]

:bravo:

I will order a module and have a fiddle with it.

[exxos]

My modules look to have come! Was quick from china! Now to find some time....

I wonder if there are wireless modules of some sort as well...

[olivier.jan]

I haven’t heard of wireless modules, but a cheap Esp8266 or esp32 and a voltage converter could do the job.
Plug an esp32 serial port on the MFP through a level converter, compile a simple sketch and you have serial over BT.

[olivier.jan]

So I gave it a try with an ESP32 I had, and it works pretty well.
Just needed to add a little level converter to avoid burning the ESP32, but overall pretty straightforward.

esp32.jpg

You can easily detect the BT device and use it from a SerialTerminal software.(BTW if someone knows a good Serial Terminal software for macOS, mine keeps crashing).

BT.jpg

serial.jpg

The only annoying thing: the code is very complex :lol:

Code: Select all

//This example code is in the Public Domain (or CC0 licensed, at your option.)
//By Evandro Copercini - 2018
//
//This example creates a bridge between Serial and Classical Bluetooth (SPP)
//and also demonstrate that SerialBT have the same functionalities of a normal Serial

#include "BluetoothSerial.h"

#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif

BluetoothSerial SerialBT;

#define RXD2 16
#define TXD2 17

void setup() {
  Serial2.begin(9600,SERIAL_8N1, RXD2, TXD2);
  SerialBT.begin("ATARI"); //Bluetooth device name
}

void loop() {

  if (Serial2.available()) {
    SerialBT.write(Serial2.read());
  }
  if (SerialBT.available()) {
    Serial2.write(SerialBT.read());
  }
}

Now using a 240Mhz MCU to provide a BT Serial is a bit overkill. But it open the doors to other mods, BT keyboard and mouse ? Wifi ? ACSI SD Card ?


Anyway, instead of playing with ESP32 I should be fixing this RAM issue first...procrastination...

Olivier