On 10/15/20 10:13 AM, Josh Malone wrote:
That sounds awesome, Brian! I'm excited to build one of these once the
PCB is ready.
The RAM version is now verified. FINALLY
The ROM version is not verified yet. I think I may actually just have a
bad chip or a bad solder on this first one I just built, because the
pinouts look ok. I'm getting good chip ID and able to read 256K of data
if I try to read the chip. But when trying to write it says bad chip id
sometimes, and sometimes writes fine but the verify fails and shows no
actual data was written.
But I don't think the rom version is of much use yet anyway because I
don't think we know exactly what to put on it anyway. I plan to
experiment on that, after I have a card that works. But right now, we
have no rom image to load onto it, it would only be useful for the
purpose of starting to figure out how to make a rom image in the first
place.
The RAM version is immediately and directly useful.
The RAM version still has an issue merely that it's difficult to build
because of the diodes. They are too small, and the markings that are
supposed to be on top to indicate the polarity are too faint to actually
see, even with light and magnification. The tiny size is actually
tolerable, just tweezers and magnification and patience, but it's
annoying not being able to tell which way to install the thing and
having to actually test with a meter.
But if you can deal with that, it works now. It only gets better from
now by finding a more convenient diode.
There are actually 2 versions of each card, a full size pcb that doesn't
use a 3d-printed carrier, and a small pcb that snaps into a carrier.
I've decided the 3d-printed carrier version of the RAM card doesn't make
any sense and I'll probably remove it, at least from the readme. Maybe
leave the kicad files there off in an extras/junk directory. The small
ram card has no room for a battery, just a cap, and the cap only gives
about 10 minutes of memory life. All along I wondered "why did they even
make a RAM card? What good is a card that erases as soon as it loses
powwer?" And then I saw a scan of a catalog ad that said the ram card
was battery backed. So they probably never did make a card that lost
it's memory when ejected or turned off, so there is no point in making
one now either.
And given that, we might as well not bother for the ROM card either.
Might as well just have two simple plain cards with no carrier. Simpler
to assemble, and cheaper to buy the parts.
Which means might as well remove the model for the carrier too. Too bad
I really like it. :/
I have found that PCBWAY allows to publish a "buy this board" similar to
OSHPark. I posted the ROM cards and the programming adapter on PCBWAY,
but haven't done the RAM cards yet. I'll probably get that up in a few
hours.
The PCBWAY boards would be slightly preferrable because you can order
them in the full allowable thickness (1.0 for the RAM card, 1.2mm for
the ROM card) rather than just 0.8mm. oshpark only offers 1.6mm and
0.8mm. Although, OSHPark's 0.8mm is significantly stiffer than JLCPCB's
0.8mm, so maybe that's not such a big deal. I don't know what PCBWAY's
boards are like yet but they are on the way.
So at this point you can wait a little longer for the pcbway review and
for me to find some other answer for those diodes, or if you were
impatient, as of now you could order the pcb and bom currently posted
for the RAM card, and I would only bother with the battery-backed
version of the RAM card.
https://github.com/bkw777/WP-2_IC_Card
--
bkw
Is the flash version able to be written by the WP-2? Or
is this just for running z80 programs on the WP-2 which you flash
externally?
-Josh
On Thu, Oct 15, 2020 at 12:45 AM Brian White <b.kenyo...@gmail.com> wrote:
The last piece I as waiting for came in today and the ram card works both
mechanically and functionally.
