C0135-forth-ihex not running

[johnsfchan]

@TG9541 , hi. I am a computer beginner learning eForth.

I have purchased a C0135 like board and the MCU is STM8S003.

I can load and run github.com/TG9541/stm8ef/release 66 version of C0135.
An OK prompt appears and I can show all 'words'.

But I failed to load and run github.com/TG9541/stm8ef-modbus/release 10 version of C0135-forth.
No OK prompt.

I have already gone through all messages in the discussion area but cannot find any hint.

Please kindly help.

[TG9541]

@johnsfchan The default C0135 board configuration uses the STM8S103 UART for the console. A Modbus application needs a UART for that fieldbus. As the STM8S103 only has one UART a GPIO is used for half-duplex terminal communication - in the C0135 MODBUS case it's PD1/SWIM (which I once called SWIMCOM).

STM8 device    .      .----o serial TxD "TTL"
               .      |      (e.g. "PL2303" USB serial converter)
               .     ---
               .     / \  1N4148
               .     ---
ICP header     .      |
               .      *----o serial RxD "TTL
               .      |
STM8 PD1/SWIM-->>-----*----o ST-LINK SWIM
               .
NRST----------->>----------o ST-LINK NRST
               .
GND------------>>-----*----o ST-LINK GND
               .      |
................      .----o serial GND

You'll need a diode, and you'll need to use the same connector as the one you use for programming. Communication is quite reliable, unless there is a resistor in the PC UART's TX line.

[johnsfchan]

@TG9541 hi, thank you for your quick response.

Please kindly share a photo of your set up of half-duplex terminal communication as I am very new to electronic components.

[johnsfchan]

@TG9541 I want to ask may be a stupid question:
In your youtube video: "A modular MODBUS Server with STM8 eForth" Forth2020 #24 June 2022
where is the power connection for the relay board?

Power connection has not shown in your previous STM8 device ICP header diagram.

Should I connect 3.3v of the USB serial connector to the same in the C0135 board?

[TG9541]

The question is a very valid one. I used a cheap SWIM programming dongle to supply 3.3V to the ICP port.

Note that the board is sometimes advertised as a "5V board" but that's not the case. A 5V power supply would fry the
3.3V linear voltage regulator, and maybe damage the board.

[johnsfchan]

@TG9541 thank you for your advice.

By the way, please kindly consider to update the various stm8 eforth pages to replace the linkage of e4thcom by:

existing but not working: https://wiki.forth-ev.de/doku.php/en:projects:e4thcom

new & working: https://forth-ev.de/wiki/en:projects:e4thcom.

Regards
John

[TG9541]

@TG9541 thank you for your advice.
By the way, please kindly consider to update the various stm8 eforth pages to replace the linkage of e4thcom by:
existing but not working: https://wiki.forth-ev.de/doku.php/en:projects:e4thcom
new & working: https://forth-ev.de/wiki/en:projects:e4thcom.

Thanks for the heads-up!

[TG9541]

I did one substitution in the repo and a few in the Wiki. Unfortunately the Wiki isn't searchable, and it's possible that I missed some. If you find any non-working URLs please let me know it :-)