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HP97 The journey begins - Printable Version

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RE: HP97 The journey begins - Massimo Gnerucci - 09-25-2019 05:54 AM

(09-25-2019 05:42 AM)teenix Wrote:  Hi all,

I just returned home from flying in remote West Australia and I pulled the misbehaving hard drive out of the old PC. I couldn't open it because I don't have a Torx screwdriver available, but the PCB seemed clean and no nasties. I thought why not and I gave it a few light taps and plugged it back in.

"Murphy" must be on holidays today as the silly thing worked. I guess maybe a stuck head due to old age causing the clunking sounds. Anyway I quickly got the project schematics data off it and now with some generous help from Harald and a friend of his, the design can continue.

Amazing :-)

cheers

Tony

Murphy likes making fun of Murphy, once in a while.
Good news indeed!


RE: HP97 The journey begins - BobVA - 09-26-2019 02:50 AM

Fantastic news - can't wait to see how this goes!


RE: HP97 The journey begins - albertofenini - 09-26-2019 09:25 AM

Good luck !!
Can't wait to see how it ends up !!


RE: HP97 The journey begins - teenix - 10-10-2019 07:03 AM

Hi all,

New boards arrived today.

I populated the power supply section and all voltages look ok.
I'll install the rest of the components tomorrow. Then there will be a bit to do as a new processor was chosen for the simpler board and all new software had to be written. It simulates ok, but real world is often different. Fingers crossed Smile

cheers

Tony


RE: HP97 The journey begins - ijabbott - 10-10-2019 07:41 AM

(10-10-2019 07:03 AM)teenix Wrote:  New boards arrived today.

I populated the power supply section and all voltages look ok.
I'll install the rest of the components tomorrow. Then there will be a bit to do as a new processor was chosen for the simpler board and all new software had to be written. It simulates ok, but real world is often different. Fingers crossed Smile

Hope it all goes well! What processor did you end up using? I can't really tell from the screenprint text on the JPEG image. The previous board looked like it had two PIC16F processors (in addition to the bluetooth module).


RE: HP97 The journey begins - albertofenini - 10-10-2019 08:26 AM

Wow !!!
It looks beautiful
Will it support the card reader as well ?
Good luck !! Beautiful work !!!


RE: HP97 The journey begins - teenix - 10-10-2019 08:28 AM

(10-10-2019 07:41 AM)ijabbott Wrote:  Hope it all goes well! What processor did you end up using? I can't really tell from the screenprint text on the JPEG image. The previous board looked like it had two PIC16F processors (in addition to the bluetooth module).

I used a PIC18 type similar to the one that was used in the Multicalc project. It has a high workload emulating all the hardware and I'll find out tomorrow if this one copes with the idea I came up with which has reduced the circuit to a single processor.

cheers

Tony


RE: HP97 The journey begins - teenix - 10-10-2019 08:33 AM

(10-10-2019 08:26 AM)albertofenini Wrote:  Wow !!!
It looks beautiful
Will it support the card reader as well ?
Good luck !! Beautiful work !!!

Thanks, the board did come out pretty tidy - hope it all works :-)
It has the same functionality as the original cpu board plus a couple of extras.

cheers
Tony


RE: HP97 The journey begins - Massimo Gnerucci - 10-10-2019 10:43 AM

(10-10-2019 08:33 AM)teenix Wrote:  
(10-10-2019 08:26 AM)albertofenini Wrote:  Wow !!!
It looks beautiful
Will it support the card reader as well ?
Good luck !! Beautiful work !!!

Thanks, the board did come out pretty tidy - hope it all works :-)
It has the same functionality as the original cpu board plus a couple of extras.

cheers
Tony

Phuntastic Tony! ;)


RE: HP97 The journey begins - Paul Dale - 10-10-2019 11:17 AM

(10-10-2019 08:28 AM)teenix Wrote:  It has a high workload emulating all the hardware and I'll find out tomorrow if this one copes with the idea I came up with which has reduced the circuit to a single processor.

If I thought I could find enough free time, I'd offer to assist tuning the software to make it handle the workload.

I'd be surprised it it wasn't possible. I'm not sure the effort required would be practical, but that's not why we're interested in old calculators Smile


Pauli


RE: HP97 The journey begins - albertofenini - 10-10-2019 12:28 PM

That means it will right?
It would be super !!
(10-10-2019 08:33 AM)teenix Wrote:  
(10-10-2019 08:26 AM)albertofenini Wrote:  Wow !!!
It looks beautiful
Will it support the card reader as well ?
Good luck !! Beautiful work !!!

Thanks, the board did come out pretty tidy - hope it all works :-)
It has the same functionality as the original cpu board plus a couple of extras.

cheers
Tony



RE: HP97 The journey begins - PANAMATIK - 10-10-2019 02:35 PM

Hi teenix

This board is phantastic. As you know I made an ACT chip replacement for the original board, but it doesn't support the card reader. If yours can also handle the card reader it is more than sure that I will be one of your customers. Also I have a PIC18 compiler and it would be a nice project to run different software, if you would allow it.

Bernhard


RE: HP97 The journey begins - teenix - 10-10-2019 09:57 PM

(10-10-2019 02:35 PM)PANAMATIK Wrote:  Hi teenix

This board is phantastic. As you know I made an ACT chip replacement for the original board, but it doesn't support the card reader. If yours can also handle the card reader it is more than sure that I will be one of your customers. Also I have a PIC18 compiler and it would be a nice project to run different software, if you would allow it.

Bernhard

The PCB has an ICSP connector so those in the know can probably have a go :-)

cheers

Tony


RE: HP97 The journey begins - teenix - 10-17-2019 10:38 AM

Hi all,

Boy what a few days. I've had enough bugs to keep the worlds bird population happy. I spent all of today trying to find a card read bug. As you might expect there is some complex code that has to execute and finding bugs in code that interacts with real hardware can be tricky. It turned out to be a comma [,] at the end of one code line that wasn't supposed to be there and the compiler did not report an error. Just about needed a magnifier to see it. [sigh]

Anyways, some good news.

The new board appears to be functional except for a [barely perceptible] flicker on the display which I will try to sort out.
I ran both sides of the HP-67 diagnostics card through the reader and it ran and gave the correct result.
I have successfully written cards and re-read them and the programs run as expected.
The original HP software also reads/writes "cards" from the external memory as it thinks it is talking to the CRC chip.
The PC software does the hardware re-flashing, transfers card data back and forth and sets a few operating options.

I still have to check the auto card read where the card is "parked" in the slot and the program encounters a Pause command, but as that is controlled by HP software, it should work - yeah right :-)

Time for a snoozzzzzzze.

cheers

Tony


RE: HP97 The journey begins - albertofenini - 10-17-2019 10:49 AM

Very good !! Congratulations !!!


RE: HP97 The journey begins - Harald - 10-17-2019 02:26 PM

Congratulations Tony, that sounds very promising!

Cheers,
Harald


RE: HP97 The journey begins - teenix - 10-19-2019 07:31 AM

Hi all,

Another fun filled day.

The next morning when I got up after my excited card reader working announcement, the bubble burst as it would not read anymore. Data was coming out of the reader chip ok, so I wrote a small piece of code to mirror the RA/RB data onto 2 spare output pins of the processor so I could see that the PIC was actually seeing the data. It showed that the PIC was missing some of the data transitions and cause a checksum error.

Fast forward 10 or so hours and still I could not figure it out. I rehashed the code over and over to try and see if that was the problem, but no go. I built a new CPU board and same problem.

Just as I was about to concede defeat (again), I looked at the pins connecting the card reader to the CPU board. With the normal CPU board plugged in, the reader circuit board can only be pushed in until it touches one of the ROM chips. With my board, it can be pushed in a little further. The connector pins taper down and pushing them into the mating holes further means the pin to hole tension reduces and the RA pin must have "just" been connecting.

I put the board in it's normal position and it was happy again. Some of the things you learn the hard way :-)

I hooked up the Bluetooth and mated it with my PC and I now have wireless connection to the HP-67 to transfer data which means you don't have to open the case. There are a few minor quirks with this but a software tweak will fix.

I loaded the card auto read test program from the HP-67 user manual page 295 and the card auto loaded on PAUSE. This also worked when the calculator was instructed to get the program from memory storage. W/DATA also works manually and from a program.

I tested the card write protect override option and when enabled, you can now easily re-write cards that were write protected. This means you can read cards and store the program on the PC or in the memory chip, which holds about 900 programs, and then if your original card fails, you can re-write it with the original code.

The completed CPU board is shown in situ below.

cheers

Tony


RE: HP97 The journey begins - albertofenini - 10-19-2019 07:37 AM

Congratulations!!!
Learning the hard way is the only way ...
This weekend we will work over a HP67 that does the same
RA RB very goods but still always the same Error message on the display
Also sometimes with no reasons the card get stuck ...
Happens with two different card readers so will see ...
You did a great job !!!!


RE: HP97 The journey begins - Harald - 10-19-2019 08:31 PM

(10-19-2019 07:31 AM)teenix Wrote:  Hi all,

Another fun filled day.

The next morning when I got up after my excited card reader working announcement, the bubble burst as it would not read anymore. Data was coming out of the reader chip ok, so I wrote a small piece of code to mirror the RA/RB data onto 2 spare output pins of the processor so I could see that the PIC was actually seeing the data. It showed that the PIC was missing some of the data transitions and cause a checksum error.

Fast forward 10 or so hours and still I could not figure it out. I rehashed the code over and over to try and see if that was the problem, but no go. I built a new CPU board and same problem.

Just as I was about to concede defeat (again), I looked at the pins connecting the card reader to the CPU board. With the normal CPU board plugged in, the reader circuit board can only be pushed in until it touches one of the ROM chips. With my board, it can be pushed in a little further. The connector pins taper down and pushing them into the mating holes further means the pin to hole tension reduces and the RA pin must have "just" been connecting.

I put the board in it's normal position and it was happy again. Some of the things you learn the hard way :-)

I hooked up the Bluetooth and mated it with my PC and I now have wireless connection to the HP-67 to transfer data which means you don't have to open the case. There are a few minor quirks with this but a software tweak will fix.

I loaded the card auto read test program from the HP-67 user manual page 295 and the card auto loaded on PAUSE. This also worked when the calculator was instructed to get the program from memory storage. W/DATA also works manually and from a program.

I tested the card write protect override option and when enabled, you can now easily re-write cards that were write protected. This means you can read cards and store the program on the PC or in the memory chip, which holds about 900 programs, and then if your original card fails, you can re-write it with the original code.

The completed CPU board is shown in situ below.

cheers

Tony

Wow! Can't wait to get one Smile

Cheers,
Harald


RE: HP97 The journey begins - teenix - 11-07-2019 11:46 PM

Hi all,

Still testing the HP-67 CPU replacement and appears to be going ok.


I have made some progress on the HP-65 CPU board replacement.

The PCBs should be here next week, the code has been written and mostly tested, so I should have one assembled soon and if the circuit works, start debugging.

While sorting out the code that does the CRC emulation for the 65 card read/write I noticed something. The read/write data is reversed in the 65 which may explain the incompatibility issues mentioned in the 65/67 restoration threads.

The sense chip parts are listed as

1826-0158 for 65

1826-0322 for 67,97,82104A

The circuits for the 65 and 67 show the same pin outs on these chips.

However, on checking the data with an oscilloscope I see the data reversal.

HP-65
RA and WA are associated with read/write [1] bits
RB and WB are associated with read/write [0] bits

HP-67
RA and WA are associated with read/write [0] bits
RB and WB are associated with read/write [1] bits

So swapping the sense chip between calculator models should still work as long as you only use cards that were read/written with the same sense chip.

cheers

Tony