HP97 The journey begins

[teenix]

Hi all,

I have done about 95% of the Spice code, still waiting on processor chips.

One good thing, I received some processors for the 65 and 67 CPU boards, so they can be made again :-)

I am still working on the ROM replacements and the results so far look ok.

The traces in the top part of the attached image shows the Phi1, Phi2 and SYNC signals, followed by the ROM address which is starting at address 0h. These signals are generated by a simplified ACT processor.

The next trace is the output from the ROM replacement IC which is programmed for the HP-92 ROM 0 chip, 1818-0346.

$0000 0D0 display reset twf
$0001 1AE a + 1 -> a[x]
$0001 1AE a + 1 -> a[x]

The lower scope shot shows a close up of the data stream at address $0001 and how it mimics the real data coming from a HP ROM IC. The instruction in the lowest trace can clearly be seen as $1AE, LSB first - a + 1 -> a[x].

The ROM 0 IC also outputs data to the anode driver and this is taken care of as well - not shown.

I'm expecting next gen circuit board in next few days. The first ones didn't work as expected and led to a lot of head scratching to source appropriate parts.

Fingers crossed.

cheers

Tony

[teenix]

Hi all,

After much work with the Spice board, getting there.

cheers

Tony

[Massimo Gnerucci]

(02-07-2023 06:02 PM)teenix Wrote:  After much work with the Spice board, getting there.

The Amazing Tony!
(as usual)

[Harald]

Looks great! When can I get a prototype board?

Cheers,
Harald

[teenix]

(02-07-2023 10:07 PM)Harald Wrote:  Looks great! When can I get a prototype board?

Cheers,
Harald

Soon I hope :-)

I just turned the new board on for the first time with the DIP micro. I still have some software testing to do with it, and also some mechanical testing - fitment, keys, switches etc. It has been a bit complex to set this up, but my hope is the new one will just "pop in" the original casing and away it goes.

Although I have a USB battery charge circuit built onto the battery connector board, with a low charge rate, I'm not sure whether external charging might be better given that a faulty LiPo battery might overheat. An external USB charger for these batteries is only a few dollars.

cheers

Tony

[Harald]

(02-08-2023 12:47 AM)teenix Wrote:  

(02-07-2023 10:07 PM)Harald Wrote:  Looks great! When can I get a prototype board?

Cheers,
Harald

Soon I hope :-)

I just turned the new board on for the first time with the DIP micro. I still have some software testing to do with it, and also some mechanical testing - fitment, keys, switches etc. It has been a bit complex to set this up, but my hope is the new one will just "pop in" the original casing and away it goes.

Although I have a USB battery charge circuit built onto the battery connector board, with a low charge rate, I'm not sure whether external charging might be better given that a faulty LiPo battery might overheat. An external USB charger for these batteries is only a few dollars.

cheers

Tony

Well, I guess there is no big difference between a calculator and a mobile phone in that respect. Faulty batteries aren't very common but occasionally something goes wrong. For the WP34s Lipo board I was a bit conservative with the charging voltage. I haven't heard about any problems, but maybe that was just pure luck. I am not sure what to recomend here.
If I were to make the decision just for my own calculator, I would go for a battery that is charged inside the calculator.

I haven't done a lot of calculator related stuff recently (due to lack of time mainly), but I am very much looking forward to this one.

Cheers,
Harald

[Etienne Victoria]

FWIW, I can attest that the 2 34S I have equipped with Harald's LiPo boards have been used and abused by both my daughters throughout their engineering curriculum.

This includes enduring anarchic charging and discharging, heavily tampering...

The overlays did not make it but the calculators did and are still going strong :-)

Cheers

Etienne

[Oulan]

Hi,

Just to be complete, here is the source of the HP97 rom and the patches for making an HP97 and an HP97+ (see LINK). Use ass97.py (sorry for the name) to assemble the source to 2 bin files.

Have a nice day

Olivier

[teenix]

Hi all,

Just received the prototype circuit boards for 19C.

Fun times ahead :-)

cheers

Tony

[Harald]

(02-23-2023 02:24 AM)teenix Wrote:  Hi all,

Just received the prototype circuit boards for 19C.

Fun times ahead :-)

cheers

Tony

Do you have a 19C to play with?
Bernhard still has mine and asked several times if I wanted it back. We can ask him to ship it to you if you need one.
Edit: it is not fully working though!

[teenix]

(02-23-2023 08:13 AM)Harald Wrote:  Do you have a 19C to play with?
Bernhard still has mine and asked several times if I wanted it back. We can ask him to ship it to you if you need one.
Edit: it is not fully working though!

Hi Harald,

That's very generous and thanks for the offer. I have one here that I tried to repair for a Forum member, but it had a failed IC so I thought I would try to put together a new CPU board and hopefully ship it back fully working again.

It has been a while, and now that I look back into this, after having to get a new laptop in the meantime, I had the donor details stored on the old laptop which now won't boot, a LED comes on but that's it :-(

Somewhat embarrassing. Hopefully the owner sees this message and sends one in return, otherwise I'll broadcast one on the Forum.

I got the latest Spice board today as well, so I am populating it now. With the Spice model I realized I didn't need a separate storage chip for constant memory, so hopefully the new software works for this. You can remove the battery indefinitely and it will still retain the last memory.

cheers

Tony

[Harald]

(02-23-2023 09:09 AM)teenix Wrote:  With the Spice model I realized I didn't need a separate storage chip for constant memory, so hopefully the new software works for this. You can remove the battery indefinitely and it will still retain the last memory.

Where do you store the data now?

[Massimo Gnerucci]

(02-23-2023 10:50 AM)Harald Wrote:  

(02-23-2023 09:09 AM)teenix Wrote:  With the Spice model I realized I didn't need a separate storage chip for constant memory, so hopefully the new software works for this. You can remove the battery indefinitely and it will still retain the last memory.

Where do you store the data now?

Probably here.
:)

[teenix]

(02-23-2023 11:14 AM)Massimo Gnerucci Wrote:  Probably here.

I guess in a hundred years or so and they check out a stored program there it might "Spice" up their life :-)

[teenix]

(02-23-2023 10:50 AM)Harald Wrote:  Where do you store the data now?

Still on a memory chip which is used on all the replacement boards, the PIC processor internal memory is too slow for the task and not enough there. The method I have chosen means the external one can do it much faster when required.

[mfleming]

(02-23-2023 09:09 AM)teenix Wrote:  It has been a while, and now that I look back into this, after having to get a new laptop in the meantime, I had the donor details stored on the old laptop which now won't boot, a LED comes on but that's it :-(

A USB to SATA interface cable can be had at a reasonable price from Amazon or elsewhere. Try opening the laptop case to see if you hear the drive spin up. If so there's a chance you can remove the drive and mount it via the cable. Perhaps the boot block or OS image was trashed but the data is still there. Recovery of data is much more complicated if the root directory is corrupt, but still possible (speaking from hard experience)

~Mark

[teenix]

The drive is spinning, but the rest appears dead. I think I have a hard disk via USB adaptor somewhere in a box.

[teenix]

Hi all,

The Spice is almost there (tongue in cheek) Way more work than I originally thought. The 34C is shown in the image but the module has selectable 31E, 32E 33C, 34C 37E and 38C.

The keyboard had some issues and turned out to be a poor design for the circuit board pad contact area and only hard key pressure would work. They were redesigned and now seems ok to use. The original keys may have worn a bit over the years so I don't think it will be as good as new, but the new membrane pads feel quite good. The back case also seems happy when attached with the new innards.

The display is a tiny bit dimmer than the original. The extra circuitry required to power it with external drivers (which have to be discrete parts) was not going to fit in the board space available, so they have been omitted. I doubt it will make much difference and maybe the slight drop in LED current might prolong their remaining life.

I will connect the battery board soon and make sure the USB charger is working and the battery is powering everything ok. There is a bypass circuit added to the charger so the calculator should work while on charge.

The PC software has been updated to recognize the Spice. Just have to do a full test and see that the software is behaving and update the help file.

Install should be pretty easy. There is no soldering required, so once the original is disassembled, it should take a couple of minutes to insert the display and click the board into place and then put the back cover on.

I am not going to supply the battery and USB charge cable. They can be found on the web for a few $.

cheers

Tony

[tangdfx]

Hi，Tony

Great news. I am eager to place an order.

[Harald]

Congratulations Tony! Looks great!