W65C265SXB ANS Forth
This project builds a Forth environment for a WDC W65C265SXB which can be accessed via a USB serial connection to the ACIA port. (I use a cheap PL2303 module with jumper wires acquired from ebay).
The code is split into two modules namely:
The w65c265sxb.asm file is a general purpose system reset and UART handler.
The ans-forth.asm file is implements the forth environment. This file includes device.asm to implement hardware specific words.
A number of include files are used to support the code, namely:
The w65c816.inc file contains useful definitions and macros for the W65C816 processor.
The w65c265.inc file contains definitions for the hardware built into the W65C265 processor.
The w65c265sxb.inc file contains hardware definitions for the WDC W65C265SXB development board.
The code in this repository builds a functional Forth environment that can execute standard commands and compile new words.
W65C265SXB ANS-Forth [16.04] : STAR ( -- ) 42 EMIT ; Ok : STARS ( n -- ) 0 DO STAR LOOP ; Ok CR 7 STARS *******Ok : SQUARE ( n -- ) DUP 0 DO DUP STARS CR LOOP DROP ; Ok CR 6 SQUARE CR ****** ****** ****** ****** ****** ****** Ok
I will continue to add documentation, more words and debug.
- The generation of new lines during command entry needs to be improved.
Forth in ROM
The latest version of the code builds an S28 version that runs from RAM and a S19 version that is converted into a 32K ROM image that can be loaded into the SXB's flash ROM chip (if installed).
To load the image use the W65C265SXB-Hacker program to disable the WDC ROM, erase the default flash bank and the XMODEM download the image. The commands are:
F 0 E X 8000
The current image still expects a USB serial adapter on UART0. The ROM does not start with the 'WDC' character sequence that would cause it to auto execute so you need to start it with a 'G 00:8004' command in the Mensch monitor.