Re: Signetics Datasheets for Apple 1 Project

["Bill Garber" <willy46pa@comcast.net>]

"David Wilson" <david@uow.edu.au> wrote in message 
news:432505a1$1@news.uow.edu.au...
> "logjam" <grant@cmosxray.com> writes:
>>Also, have you ever heard of a HAL?  From what I've found it stands for
>>Hard Array Logic and was used in Apple IIe/early Macintosh boards.  The
>>images of the HAL in the fpga group are from the ASG HAL on the
>>Macintosh 128k-Plus.
>
> A HAL is to a PAL as a ROM is to a PROM. Basically it is mask programmed
> at the factory rather than having fuses burned to personalise it before
> it gets inserted into the circuit board. HALs and ROMs are cheaper (if
> you buy large enough quantities) than PALs and PROMs (you do not have to
> spend time programming and then testing them - they come pre-tested from
> the manufacturer).
>
> In the IIe the Timing Generator chip is a HAL16R8. You could replace
> it with a PAL16R8 if you programmed it appropriately.

I'm not sure IIRC, but I believe I may have a IIe with
a PAL in that very spot. Over to the left side behind
the Aux slot. Maybe they didn't have any HALs that day
and decided to continue building some with PALs.  :o)

I'll look to see if I still have it. Would be kool.

Bill Garber