OT: But for the vintage CPU guys: Intel 8008 clock

[Ben]

Philip Pemberton wrote:
> Ethan Dicks wrote:
>>> from the site "Every year [Len Bales] designs and builds a new 
>>> clock. His
>>> 2006 clock runs on the classic Intel 8008 microprocessor. The design is
>>> definitely not for the faint of heart...
>>
>> Wow, that's a lot of breadboarding.
>
> I did roughly as much when I built up my 6502 board. If memory serves, 
> I had a GAL16V8AQ PLD (address decoder), 28C64 EEPROM, and a RAM chip 
> on one chunk of breadboard, a W65C02A (WDC CMOS 6502) on another, and 
> a TI 16C550 UART on the third.
>
> I don't think I got the breadboarded version stable at much more than 
> 2MHz, but the Eurocard version runs quite nicely at 10MHz, with a full 
> complement of I/O cards (CPU/RAM/ROM, UART, SP0256A-AL2 speech 
> synthesizer).
>
> I've never plucked up the courage to put a scope on the backplane, 
> though. Phi-0 and Phi-2 are probably rather messy, and I suspect SEL0 
> thru SEL3 aren't in much better shape...
>
> Schematics (hand drawn with a Rapidograph, no less!) are at 
> http://www.philpem.me.uk/elec/6502/ if anyone wants to have a look.
>
> Ultimately, I got to the point where I could make it run EhBASIC and 
> speak, then more or less ran out of things to do with it. At some 
> point, I really should tie a MOS 6581 "SID" sound chip to the bus and 
> see what happens... Or maybe a disk controller...
>
Well build it while you can get chips ... I was going to do CPLD 
computer design, until I got a virus  on my computer
and  had to  reinstall  windows a few days ago. So I am back to TTL or 
rather LS TTL since I can't get real TTL
from my favorite supplier - Unicorn Electronics. I may have to throw in 
a few 74F283's or 7483's in to meet my
speed requirements on the increment/decrement data path. Here all I need 
is a brain (optional) a pen and a pad of quad
paper and of course DATA sheets. Ben.