PDP-8 on FPGA project & where is Hans Pufal?

[bfranchuk at jetnet.ab.ca]

Philipp Hachtmann wrote:

> There's ONE problem: SIMH on a modern PC runs MUCH faster!

Why worry , use a older PC :)

> The times are only the synthesis estimates! In reality, it gets other 
> timings (currently it wants 17ns - but runs with 10 *g*)

But who knows when the timing will getya ??


> 20ns per stage? Ok, I understand...
> 
>> The 20 bit cpu alas can't be a (fictional) single chip cpu since I 
>> can't fit it into a 48 pin dip.
>> I am two pins extra. [1]

I said fictional ... I am using sockted 84 pin PLCC's... I got the chips
and I got the sockets.  Now I can't find a PCB  layout program with
a 84 pin plcc socket. I am using DipTrace and have made up my own
socket but I am working on logic design.

> ?? There are other packages :-) Xilinx Spartan-II, Spartan-3 and 
> Spartan-3e at least
> can be found in handy 144 pin packages. They *can* be soldered manually. 
> It's easier than
> everybody thinks. BGAs are quite impossible... And all the bigger Chips 
> (>400k) are only available
> in BGA package :-(

I am trying for thru the hole parts here,I don't need micro-microchips :)
I just was looking my logic again and I can  multi-plex my needed inputs
so the logic is not dirty as I thought - just add a quad 2/1 multiplexer.
Other than clock and front panel switch debouncing and encoding, most of
my TTL is just glue.
This gives me I about  8" x 10" PCB for the CPU, I/O chips and 96Kb of memory
and some space for EEPROM's.  The other PCB will be the front panel
with about 60 lights and 24 switches.




> Philipp :-)
> 
>