30 Mar
2006
30 Mar
'06
4:54 a.m.
Is this the unit that would take the SNAP
development ROMs?
The SNAP ROMs came in a unit that plugs into the side of the HHC and
has sockets for four 24 pin EPROMs. Unfortunately, my SNAP ROMs no
What else is in the unit? My investigations of the logic board
have shown
that there are a number of chip select lines brought out on the
expansion
connecotr, but there's no sane way to put 4 EPROMs directly on that
connector. I would guess at least there's a 2-4 line decoder. And
probably some transsitors to swich the Vcc to the EPROMs to save
battery
power (the HHC itself does that trick). These components may well
be SMD
on the back side of the board, BTW.
There are four M74LS08P chips on the board as well as the EPROMs.
I am wondering if it would be possible to make a clone of this unit,
using, say, one 16K or 32K EPROM suitable connected.
That would be a good idea. In fact, I obviously have a programmer
that can handle the chips since I was able to read their contents.
Anyone know where I can get some HN462532G chips?
I don't know enough about hardware to figure out how the unit works
myself. I guess I could send it to you if you want to take a look.
longer work since a few of the pins broke off one
of the EPROM chips
when I removed it to read the contents on my EPROM programmer. I've
purchased some machined pin sockets on someone's suggestion but I
don't seem to have the skill needed to solder the EPROM pin stubs to
the socket pins. The good news is that I *did* get images of the
EPROMs before the pins broke off this one chip.
Are the EPROMs a rare type? Or could you get new ones and burn the
images
into them.