On 3/9/21 3:52 PM, Tom Wilson wrote:
If I understand correctly, this gives you an IGP header for the card
slot in a Tandy WP-2 word processor?
Yep.
A while back I wondered if it would be possible to make a card for it.
The physical component turned out to have a suitable answer. The contact
inside are a single row of male pins, 1.27mm apart, and they make single
row pin headers in 1.27mm pitch, and it turns out possible to solder a
pin header to the edge of a pcb and it fits right in. The only special
thing is you can't use a regular 1.6mm pcb, it has to be 1.2mm or
thinner, 1.2mm ideally, but oshpark's 0.8mm option is ok too.
Then, looking at the service manual, the interface to the slot looked
simple. Basically just all the lines to a standard sram or rom plus a
couple simple control signals.
So I tried it. I dew up a simple card with a chip, and it worked!
Refined it a few times and now I have this, which works well.
(actually I haven't tested the version with the write-protect switch
yet, but the previous version was no different except for the
write-protect switch and that is tested.)
https://www.pcbway.com/project/shareproject/WP_2_RAM_IC_Card.html
But now the question is the ROM card.
The WP-2 manual claims it supports two kinds of cards, ram and rom.
The ram card was easy. It's physically more parts with a battery and
stuff, but it's just empty space that the WP-2 firmware formats and
let's you store files on it.
But the ROM card is a mystery. Electrically, no problem. But there are
no example rom images to load onto it, and I have no idea how the main
rom uses a rom card. I did try formatting a ram card and then dumping an
image of the sram and writng it to the rom, so see it it was used like a
read-only filesystem, but it didn't do anything except lock up the machine.
So I want to watch the bus while playing with the machine with a rom
card inserted just to see what I can see. One of the pins on the
connector is specifically just to indicate to the WP-2 what kind of card
is inserted, ram or rom. I'm hoping I'll see some sort of attempted
access. That probably still won't tell me anything useful since I'm not
a z80 machine language hacker. "Great now I know it tries to read the
contents at address ####." but whatever, gotta start somewhere and you
never know until you try.
--
bkw
Tom Wilson
[email protected] <mailto:[email protected]>
(619)940-6311
On Tue, Mar 9, 2021 at 12:46 PM Brian K. White <[email protected]
<mailto:[email protected]>> wrote:
"Your PCBs have been shipped by PCBWay"
Aww yeah gonna let the smoke out now...
https://www.pcbway.com/project/shareproject/TANDY_WP_2_IC_Card_Breakout.html
<https://www.pcbway.com/project/shareproject/TANDY_WP_2_IC_Card_Breakout.html>
A year or two ago I got one of those slick little Saelee Logic 16
channel logic analysers, and a Bitscope Micro which can act as
another 8
channel. And my Rigol has 4 channels... I should be able to watch the
entire bus at once.
Though, maybe not usefully, with the control, data, and address
lines in
3 different logs from 3 different devices that probably cannot be
accurately synced up accurately enough.
--
bkw
--
bkw
