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New member original super board II owner

Posted: Mon Mar 16, 2015 12:18 am
by drwass2
Hello guys
I've had my supper board II since the introduction probably about 1978 or so.
Way back in the old days, I designed a very great mode to the video interface to convert the screen to twice as many characters across and half the lines down using very minor (I believe it was about 4 cut traces) and adding two 7400 chips.
The display becomes very easily readable due to the space between lines vertically and the the normal size characters across. It steals the characters RAM space from the line below and sneaks it into the space above between the next character so it doubles the characters. (no extra RAM needed) If I can dig out my machine and if it still works (i believe it does) I will try to send some pictures. One 7400 chip is set up as a monostable vibrator to generate a new dot clock. The other chip is a mux to switch between the new mode and the old mode so you can easily switch back and forth. You can even make it under program control by controlling the mux from a video bit that is off page. It really is a simply and very sweet modification. Of course I added software so that everything comes out normal. It is just a few bytes that I tack unto the free space at the top of (note sure here) page 1.

also wrote a very small program that uses the vertical sync signal to generate an interrupt which runs a little clock like routine that keeps time by actually doing the addition on the ASCII characters stored in the corner of the video screen.
Again this software is just a few bytes hidden in the extra memory space.

I never had a floppy at the time and kept the programs on audio tapes. Hope they are stil readable.

I got my hands on a baudot teletype and wrote a little translate and bit banging routine using one of the keyboard lines as output to drive a transistor and got some great hard copy.

then I wrote a 1) Disasembler, 2)a Basic renumber routine, 3)A Basic Trace routine \
I used to talk on the phone with some programmer up at OSI who gave me a great number of addresses of routines in ROM which I was able to use in my programs and save me lots of trouble and time writing my little routines.
If these things are not widely known now I could try to put together a little blurb on them.

Any way, I really love the 6502 and think it is a great little processor. I've been out of touch for at least 35 years now, and want to get back into some hands on, hardware software things. I've played with basic stamp, pics, propeller, arduino, etc.

I will have to review this site and see whats going on.
Hope to see some of you at Vintage Computer Festival EAST in New Jersey.

Evan

Re: New member original super board II owner

Posted: Mon Mar 16, 2015 7:09 am
by MK14HAK
Welcome Evan.
It will be interesting to see if your Superboard is still working. You will find most info you may need on osiweb and help via this forum should you require it.
We would certainly be interested in your software and I hope your tapes are still readable. Any blurb as well !
You join at a time when there are a few interesting hardware projects going on and a drive to collect and preserve any software for the OSI systems. We would be grateful for any contribution.
Vintage Computer Festival - must put that on my bucket list. :mrgreen:
Mike

Re: New member original super board II owner

Posted: Wed May 13, 2015 5:22 pm
by Scott Larson
drwass2 wrote:also wrote a very small program that uses the vertical sync signal to generate an interrupt which runs a little clock like routine that keeps time by actually doing the addition on the ASCII characters stored in the corner of the video screen.
One of the exciting projects I did was build a real time clock using an inexpensive chip that was very easy to memory-map to the C1P and Superboard II. If I remember right, everything including the date was stored in BCD so setting the time and date was just a few POKEs, then it was accurate to something like two seconds a month.

Well, the second chip was anyway. The first one ran for about a week and then start speeding up and slowing down in a ridiculous fashion. And no, I didn't put it in a socket because who would have thought it could fail?

Re: New member original super board II owner

Posted: Thu May 14, 2015 12:18 am
by MK14HAK
Scott, do you remember the RTC chip you used ?

Re: New member original super board II owner

Posted: Thu May 14, 2015 11:38 pm
by bxdanny
It sounds like your video mod is the same one OSI later implemented themselves in the 600 Rev. D/C1 Series II. But you had it first. 48 characters visible on a line, with the lower left corner of the visible screen being D3CC? Did you have a way of switching between 24-character and 48-character modes? Also, can you remember the name of your contact at OSI?

Re: New member original super board II owner

Posted: Wed Jun 10, 2015 11:45 pm
by Scott Larson
MK14HAK wrote:Scott, do you remember the RTC chip you used ?
No, I don't remember.

Re: New member original super board II owner

Posted: Thu Jun 11, 2015 9:29 pm
by Scott Larson
After looking around, I'm pretty sure I used the MOS 6526 for an RTC. I remember I used the same chip for a parallel printer interface (replacing my crude 8 bit latch circuit) and a second serial port for a modem. The 6526 provides both of those. It also stores the time and date in BCD format.

Kind of a nifty chip at the time.