STM8 eForth experiments with the XY-LPWM board

Hardware

J3 ICP Pin	Signal
1	+3.3V (supply)
2	NRST
3	SWIM and serial console
4	STM8S003F3P6 Vcap (do not connect)
5	GND

Recently XY-LPWM modules are based on the Nuvoton N76E003AT20 controller which is a MCS51 type "pin-compatible" replacement for the STM8S003F3P6 which is otherwise incompatible. A new board has appeared that uses an unknown µC in an SO16 package. This means it's getting more risky to use this board if you intend modify it.

This chip must be replaced for using STM8 eForth.

Building

Run make on a Linux system to...

• pull dependencies
• build the STM8 eForth board package
• transfer board Forth code from XY-LPWM/board.fs

STM8 eForth Console

In order to free up the STM8S UART for development, the Forth console uses a simulated half-duplex serial interface on PD1/SWIM. The serial console and an ST-LINK V2 (or a corresponding USB dongle) can be connected in parallel:

XY-LPWM        .      .----o serial TxD "TTL"
               .      |      (e.g. "PL2303" USB serial converter)
               .     ---
               .     / \  e.g. 1N4148
               .     ---
ICP header     .      |
               .      *----o serial RxD "TTL
               .      |
VCC------------>>-----+----o ST-LINK 3.3V
               .      |
Vcap----------->> NC  |
               .      |
STM8 PD1/SWIM-->>-----*----o ST-LINK SWIM
               .
NRST----------->>----------o ST-LINK NRST
               .
GND------------>>-----*----o ST-LINK GND
               .      |
................      .----o serial GND