4 Dec
2019
4 Dec
'19
6:55 p.m.
I have a TRS-80 Model III with a IV upgrade in it (non gate array).
I have a hunch that one or two of the HALs are bad (the primary one
being 8075208).
Anyone have the JED files to program any of these HALs into PALs or
GALs ?
Anyone know a source for these ?
Anyone know if these can be read, or if they are protected (for
example, if I were able to borrow some working ones, could they be
duplicated ?) ?
Thanks,
-- Curt
5 Dec
5 Dec
9:39 a.m.
On Wed, Dec 4, 2019 at 11:08 PM rescue via cctalk <cctalk at classiccmp.org>
wrote:
I have a TRS-80 Model III with a IV upgrade in it (non
gate array).
I have a hunch that one or two of the HALs are bad (the primary one
Anyone know if these can be read, or if they are protected (for
example, if I were able to borrow some working ones, could they be
duplicated ?) ?
Last year I read most of the PALs and HALs of a TRS-80 Model 16B main board
(same as Model 12 main board). I was surprised that none of the PALs were
protected, and even more surprised that some (but not all) of the HALs
could be read as PALs.
5:49 p.m.
On 12/5/19 12:39 PM, Eric Smith via cctalk wrote:
Last year I read most of the PALs and HALs of a TRS-80
Model 16B main
board (same as Model 12 main board). I was surprised that none of the
PALs were protected, and even more surprised that some (but not all)
of the HALs could be read as PALs.
Eric, first, I want to thank you for the
excellent M2 ROM disassembly
you did; while I was helping debug the MAME trs80m2 emulator your
listing was extremely helpful in tracing down the problem which
single-stepping in the MAME debugger (it was a bug in the WD1791
emulation of deleted data address marks).
Second, there is a published European patent on the Model 4 circuitry;
see http://www.freepatentsonline.com/EP0126305.pdf for the details.? The
PAL equations and pinouts begin on PDF page 31.
The 12/16B/6000 mainboard's PAL equations are printed in the service
manuals for those machines; the 6000 service manual is available on
archive.org.? But it is a bit surprising that the security fuse wasn't
blown; Jerry Ballard and Frank Durda were both unsure (years ago when I
asked them both) if the M4's PALs had the security fuse blown or not,
and at that time I didn't have the equipment to try to read them.
6 Dec
6 Dec
4:02 p.m.
On Thu, Dec 5, 2019 at 6:49 PM Lamar Owen <lowen at pari.edu> wrote:
The 12/16B/6000 mainboard's PAL equations are
printed in the service
manuals for those machines;
Some are, some aren't, and it's doesn't appear that they are 100% accurate,
though that might just be formatting errors in their reproduction of the
listings.
5 Dec
5 Dec
10:24 a.m.
On 2019-12-04 21:55, rescue wrote:
I have a TRS-80 Model III with a IV upgrade in it (non
gate array).
I have a hunch that one or two of the HALs are bad (the primary one
being 8075208).
Anyone have the JED files to program any of these HALs into PALs or
GALs ?
Anyone know a source for these ?
Anyone know if these can be read, or if they are protected (for
example, if I were able to borrow some working ones, could they be
duplicated ?) ?
Thanks,
-- Curt
It has come to my attention these HALs may be readable as PALs...
I'll have to check my programmers and see if any support reading those
on mine.... though that still doesn't give me any basis for comparison
:-(.
Anyone have a spare TRS-80 Model IV PCB that I could read the HALs
from.... or someone who can has and can read them.
Looks like I do have the HAL that supports the memory upgrade beyond
64k. Mine is not the initial Model IV Rev....
When mounted in the Model III/IV chassis, the RAM is in the bottom
right (not top left).
My PCB says 8709296 Rev C on it.
-- Curt
1847
days inactive
1849
days old
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lowen＠pari.edu -
rescue＠hawkmountain.net -
spacewar＠gmail.com