New member original super board II owner
Posted: Mon Mar 16, 2015 12:18 am
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
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