Woodstock Low Power

[PANAMATIK]

(07-26-2017 04:00 AM)BobVA Wrote:  FANTASTIC! (And congratulations on this excellent work!)

Thanks for these million questions.

Quote:- It sounds like the installation is designed for a Woodstock logic board with all the IC's removed, yes? Is it necessary / advisable to remove the power supply components as well?

You have to remove only the two display driver chips. All other components, ACT, RAM, ROM and power supply components can be left in place. You have to cut just one copper trace to get the power supply disconnected. And you have to solder 7 wires from the new circuit to the keyboard pins.

Quote: - Does it make any difference what Woodstock logic board is used as a host?

No, all of them are suitable. Perhaps the location where to cut the power line and where to solder the wires are slightly different.

Quote: - Will it use the same GPS module? Given the component removal, can it be installed facing up (assuming that will make a reception difference...not really sure if looking "through" the keyboard will be a help or a hindrance in that regard)

Yes, it will use the same GPS module. If you remove the ACT chip you can locate it face up or face down at its place. Whether it makes a reception difference is still unknown. The keyboard does not shield measurable. But it could get better, because the noisy switching power supply is not longer there. I didn't yet test it.

Quote: - Where does the new low power module fit? On the section of the logic board now holding the ACT? or on the display end of the board?

It will fit at the display end of the board. The original HP board may not be removed. The pins of the new circuit are located exactly over the corresponding pins of the removed display driver chips and will be inserted into a low profile socket there.

Quote: - Is there enough code space / IO / processor power to allow for a 1 PPS triggered/synchronized GPS time display? (The current GPS display appears limited by the accuracy of the NMEA stream and subsequent processing.)

The GPS module sends the time every second and it will be displayed immediately after receiving the time string within 8 ms or so, one 12-digit display cycle is 3,5 ms. But I have no knowledge how accurate the time of sending the time string corresponds to the UTC second.

Quote: - Can the GPS time set the RTC?

Good question! Sure, I will provide a key sequence for it.

Quote: - Any possibility for an externally accessible interconnect to load/save programs or updates? (Perhaps replacing the existing - and presumably now completely vestigial - charger pins with a recessed micro connector or something?)

Yes, the 5-pin update connector on the upper left can be connected to an USB/TTL serial converter, where you can also upload and download your programs and you can remotely operate the calculator from the PC side!

Quote:PS And, of course, what printing mode will be used for the TRACE function :-)

MAN, NORM and TRACE mode selectable !!!!

Quote:Very nice!!! Thanks for all your work on these old gems!

Thanks!

Bernhard