This version is expandable and has the following specs:
- 48 Kbytes RAM $0000-$BFFF
- 16 Kbytes ROM $C000-$FFFF *
- 256 Bytes I/O
- One serial port 115200 Baud 8N1
- On board 8 bits Parallel I/O port
On the bus two extra addresses for I/O are predecoded.
On board I/O
- Serial ACIA 68B50 $CF00
- Paralllel I/O $CF20
*IOSEL is active from $CF00-$CFFF
- CSAUX $CF60
- CSPIA $CF40
For other info look at Scrumpel8a/8b project.
Here an example screen output of my dos09 operating system for the 6809.
The OS is running in 16K RAM from $8000 to $BE00 and knows only one disk of 1.3 MB.