Keith-
Memory map
05/21/2024 at 00:50 • 0 comments0000 to 7FFF 32K RAM 8000 to 9FFF 8K Empty A000
A002 to BFFF aliasesMC6850 UART C000
FFFF16K ROM -
About the board
04/29/2024 at 11:51 • 0 commentsI bought it on eBay: https://www.ebay.co.uk/itm/175882294924
It uses a 68B09P (6809 rated at 2 MHz, with on-chip oscillator), and a 7.7328 MHz crystal.
The UART is a 68B50P (6850 rated at 2 MHz), which has problems with USB-to-serial adaptors made by FTDI due to a bug in the latter's chips.
See https://hackaday.io/project/167418-ftdi-usb-cable-problems-with-6850-acia
It is nothing amazing, just a layout of Grant Searle's minimalist design.
It does have a 40-pin expansion socket, which makes life easier if you wish to add experimental features (which I do).
In particular, I'd like to add a better serial channel device, to replace the 6850.