[sdiy] Art of electronics computer

[Veronica Merryfield]

On 2012-01-08, at 4:52 PM, Scott Gravenhorst wrote:

> 
> "Lanterman, Aaron" <lanterma at ece.gatech.edu> wrote:
>> 
>> On Jan 8, 2012, at 3:44 PM, dan snazelle wrote:
>> 
>>> Id also need a few weird logic chips and a keypad. But i think 
>> id learn a lot. Especially if i built the entire lab computer 
>> with the 68008 and did the chapters on assembly. 
>> 
>> That's a blast from the past... when I was a senior at Wash U - 
>> uhm, 1992 or 1993 - the final project in the digital design lab 
>> involved making an add-on-board to a 68000-based computer board 
>> thingy. We had to have it drive D/A converters hooked to an 
>> oscilloscope to make a raster character display.
>> 
>> Alas, my team never got ours fully working, but I don't think 
>> anyone else did either IIRC. ;) 
> 
> Wow.  I did this exact thing - raster character display using a MC6800
> (6800, not 68000) and a 555 timer in my own PLL circuit that muxed the
> bits from a parallel port to the Z axis of the scope.  It worked quite
> well actually - on an Eico 460 scope  (that's 460 kilohertz).

These must have been the default project - Portsmouth Poly, as it was then, mid 80's, same project - 6800 board, make a DVM raster characters on a scope. I got mine working. I had the advantage of most of my peers in that I had been messing with electronics and CPUs for about 6 years by then and had turned my scope into a TV with a radio receiver and a couple function generators (how to have tv in a bedroom as a kid!) plus I had been programming a Z80 and 6502 for a while. I don't think the lecturer had ever seen it completed before.