18 Dec
2008
18 Dec
'08
11:49 p.m.
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 :-)