This is a custom terminal designed to take advantage of special features within the SXB monitor ROMs, which were designed with programs of this type in mind. It provides a user interface which supports commonly-used operations and uploading programs to SRAM.
The terminal interface makes these boards as easy to use as an emulator, but with the confidence of testing against real hardware. It also makes it possible to control the boards from the PC - either with the monitor itself, or through use of the many built-in ROM routines available to programmers.
Updated the program loading to be faster. Will try to get some new binaries up soon, but I like to test them first.
Never did any serial programming before this. The FTDI chip threw me off a little at first, as it requires a time delay after each USB transaction. 16ms has been reliable, but that's a pretty long time so it pays to try to send data in larger chunks.
It's also possible to raise the port speed of the SXB, which defaults to 9600 baud. The strategy:
1. Connect at the default speed.
2. Upload a small program that calls a built-in ROM routine to raise the port speed.
3. Disconnect, and reconnect at the higher speed.
This can be done automatically, but I ended up discarding the feature for now, because it didn't make the uploading faster.
However, the uploader sends relatively small chunks of data (remember the FTDI delay) so there may be room for improvement. I suspect the ROM code could also have it's own speed limitations, but I'm not sure about that yet.
Grab the ROM reference and assembly dumps here, must-have information for the SXB's: