New V9958-Board with integrated OPL2

It’s time for another hardware upgrade. Since we really want to get our single board Steckschwein done, we are going for higher integration of our multiboard prototype. After integrating the UART to the IO-Board, we integrate the OPL2 sound part onto the V9958 video board, so the current Steckschwein multi board incarnations are reduced to three boards. We did postpone our plan to upgrade sound to OPL3 because Daniel Illgen, which we met at VCFb, convinced us with some awesome OPL2 tunes that OPL2 is still cool.

V9958 - "The WAIT" - investigation of the CPU/VDP /WAIT interface

… on the way back to munich, we had some time to do a little code review of our gfx library. thinking about the cpu to video chip timings and again read the well known datasheets of the V9938/V9958. suddenly i got an enlightenment and we came to the following conclusion. as described in the datasheet (V9958-Technical-manual_v1.0.pdf) of the V9958 there are different timings given for different kind of writes. so as far as we understand there are the following timings

WOZMON - a memory monitor in 256 bytes

The woz monitor, also known as WOZMON, is a pretty simple memory monitor and was the system software located in the 256 byte PROM on the Apple I. Wozmon is used to inspect and modify memory contents or to execute programs already located in memory. Steve Wozniak managed to squeeze all that functionality into 256 bytes. That’s right, bytes. Not megabytes, not kilobytes. Bytes. We already had attempted to get wozmon ported to our Steckschwein, but we did not succeed so far.

Switching to english

There seems to be quite some interest in our little project from outside of germany. Thanks to all who are following what we are doing. To save you the effort of putting our blatherings through Google Translate or even having to learn german, we decided switch to writing our blog articles in english. The rest of the site will be translated as we go. The hardware page has already been translated.