DIY calculator: HP30b to WP34S!

Posted: 2/25/2018 9:10:48 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

Eamoex, here's a page out of my engineering notebook from back then:

Is that clear?  If not I can translate it from the Klingon... ;-)

The process is fairly nuanced!  Wow, over 4 years ago...  Unfortunately I don't use the calculator much anymore because the keys are so unreliable, and am sadly calculator-less.  I find myself using a really old (Win 3.1? Win 95?) Symantec "SCICALC.EXE"; also the the WinXP calculator because it does HEX (but the infix notation constantly trips me up).  Tried the various free ones on my Kindle Fire 7 and didn't cotton to any, it seems I'll be forced to make my own calculator at some point.  I don't really even need programmability, just solid scientific functions and an easy to use HEX mode.  The WP34S is way overkill for me.

Anyway, I'd be interested in your take on your final result.  Good luck!

Posted: 2/26/2018 7:26:11 PM
Eamoex

Joined: 2/25/2018

"Eamoex, here's a page out of my engineering notebook from back then: Is that clear? If not I can translate it from the Klingon..."

laughing Haha! I didn't expect the full graphics. So these are your notes? Wow, very tidy, and with a nice hand, thank you very much! Not even mentioning your ability to find the thing 5 years later…

So yeah, I think it's pretty clear now. Thanks so much for helping.

I'll let you know how it turns out.

Posted: 3/1/2018 12:57:30 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

"I think you should check out this new great RPN calculator: https://www.swissmicros.com/dm42.php"

 Checked out. Thank you, Martinot, for that finding. Now saving my pocket money for it... ;-) 

Posted: 3/15/2018 1:33:08 AM
John Dick

Joined: 3/13/2018

Nice, it feels good to see one of these things. ;)

Posted: 7/21/2018 11:45:44 AM
Eamoex

Joined: 2/25/2018

Anyway, I'd be interested in your take on your final result.  Good luck!

Okay. So. I finally got around to trying this. But no win here.

I managed to erase the firmware. The calculator is in a brick state right now.

As to flashing... It's easy to determine whether it is turned on just by probing battery port voltage; it drops to 2.5-ish when it's on. I've got the exact same rig than you, with the resistors, one battery out and the connection between serial and battery grounds. Response is erratic at best. I got a few "Invalid response" messages (two different kinds, which I unfortunately didn't bother put down on paper). Now I can't get anything else but "No answer / Cannot connect to WP34s" from WP34sFlash and "Cannot connect" from MySamba.

I switched batteries at one point when I noticed the one still in the calculator had been drained, showing just above 2v. That didn't make things any better.

I use Win7x64.

I have no idea what to do next. Any help is appreciated.

Posted: 7/21/2018 1:20:54 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"I have no idea what to do next. Any help is appreciated."

Eamoex, sorry to hear you're having trouble.

I'd do some sanity checking.  Plug the USB serial cable into your PC, pull one of the resistors and use the other end of the remaining resistor to form a loopback from TX to RX.  Fire up a terminal program like TeraTerm and type into it (with local echo off) to see if the characters come back with the resistor loopback, and don't with no loopback.  Check both resistors with a DMM or with the loopback to make sure they're OK.

They say the calculator in the erased state draws significant power, so don't leave batteries in it when erased.  Get some new batteries, confirm they are fresh with a DMM, and try it again.  You can access ground via the six pad programming port, so if you are dexterous enough you should be able hold a third wire there and program it with both batteries installed.

Perhaps it's possible to permanently brick it?  I don't know enough about the hardware.  I do wish there was more feedback during the programming process, the thing just lies there, presumably thinking of England.

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