14 Nov
2007
14 Nov
'07
10:10 p.m.
Cool.
So, two things spring immediately to mind:
1) Does anyone know if the LAG from a Mac Plus is the same as (or
equivalent to) the LAG from a 512k? If so, I can take the one out of my
Plus and put it in the 512k for testing purposes. If this succeeds,
then we proceed to point 2:
2) Can anyone, given the logic equations that Grant's so kindly
provided, program a GAL16V8 for me? (For which I will gladly compensate
time & effort & parts)
Thanks!
Josh
Grant Stockly wrote:
At 03:17 PM 11/14/2007, you wrote:
There are equations for the PALs on my website:
http://www.stockly.com/forums/showthread.php?t=6
The LAG
is labeled "HAL16R8CN 8440 / 342-0251-A" so it does look
like a
custom ("HAL") chip such as what Tony
was mentioning. Guess that
would
It is. The important part of the number is the '16R8' bit. That implies
it's got 8 registered ouptuts and a total of 16 inputs to the AND array
(8 serpate inputs and 8 feedback terms from the output pins). That, of
course, accounts for 16 pins on the 20 pin package, the others are +5V,
ground, a common clock input to all the flip-flops, and a common output
enable signal to all the outputs).
It's the same architecture as a PAL16R8, and could be replaced by a
suitably-programemd GAL16V8. Not that that is any help at all without
the
PAL equations.
I will try to find all my notes on the Mac+ (but not tonight!). I know I
never figured out the PAL equations, but I might have something of use.