Commit graph

2 commits

Author SHA1 Message Date
Patrick Linstruth
c55b964921 AltairZ80: Changes to JAIR devices
I was having problems with the JAIR device keeping up with received
data at 57.6K.

This PR makes the following changes to the JAIR devices:

- Refactors the service routines into STAT, TX and RX units
- Adds a 128-byte input ring buffer
- Corrects a null pointer exception
- Adds overrun status bit implementation
- Removes a tab with spaces
2024-06-08 13:55:57 -04:00
Patrick Linstruth
3b4333dfcc ALTAIRZ80: Adds JAIR devices to simulator
Josh's Altair/IMSAI Replacement (JAIR) is a single board computer
(SBC) for the S100 bus. I created this device to assist a friend
with getting IMP and CBBS working on his JAIR. Without having a
JAIR myself, AltairZ80 to the rescue!

The following devices are added:

JAIR   - The main JAIR board I/O and ROM
JAIRS0 - Serial Port 0 (COM1)
JAIRS1 - Serial Port 1 (COM2)
JAIRP  - Parallel Port

This was a bit challenging because the JAIR uses an on-board SD
card with FAT file system to hold its BIOS and CP/M disk images.
The ATTACH command is used to mount SD card images to the
simulator. The simulator emulates the SD card interface for
read/writing SD card sectors. These images are easily mounted on
a Mac making moving files around easy. I do not know about Windows.
These same images can be written to an SD card and used with real
JAIR hardware, which may be useful for JAIR owners.

The serial and parallel ports fully support TMXR. Host serial ports
and sockets may be attached to these devices.

I am working on a GitHub repository containing an SD card image and
init script that will boot CP/M 2.2 on the JAIR simulator.

Is this device one that should be added to AltairZ80?
2024-02-01 12:52:41 -05:00