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HP-42S LCD details
10-09-2019, 06:27 AM
Post: #1
HP-42S LCD details
Curious where I could find a fairly detailed description of the 42S's LCD elements, e.g. all the elements in addition to the dot-matrix portion.
Even just a photo of a self-test with all of them visible would be instructive for me.

I've browsed the Free42 sources, but didn't find anything I could recognize offhand yet, and it doesn't seem to have emulated the self-tests. Why on Earth not? Big Grin

Thanks to anyone who can help!

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10-09-2019, 06:56 AM
Post: #2
RE: HP-42S LCD details
(10-09-2019 06:27 AM)jpcuzzourt Wrote:  I've browsed the Free42 sources, but didn't find anything I could recognize offhand yet, and it doesn't seem to have emulated the self-tests. Why on Earth not? Big Grin

It has no hardware so there's nothing for it to test. Big Grin

An idea of a test function that turns on all the elements of the display at once, for testing skin layouts, has been floating around on and off my to-do list for ages, but never got done. It's easy enough to test skins without it, I guess...

You're familiar with the 131x16 pixel dot-matrix part; the only other parts are the seven status annunciators. In order from left to right, they are ▼▲, Shift, Printer, Busy, Low Battery, G, and RAD. Out of all these, only the Low Battery annunciator is a bit of a pain in the rear to test, due to the absence of the aforementioned test instruction. You actually have to run down the battery for it to turn on.

To see all seven with their relative positions, take a look at a skin like Erik Ehrling's large 42S, https://thomasokken.com/free42/skins/des...ng42sl.gif along the bottom.
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10-09-2019, 12:27 PM
Post: #3
RE: HP-42S LCD details
(10-09-2019 06:27 AM)jpcuzzourt Wrote:  Curious where I could find a fairly detailed description of the 42S's LCD elements, e.g. all the elements in addition to the dot-matrix portion.
Even just a photo of a self-test with all of them visible would be instructive for me.

I've browsed the Free42 sources, but didn't find anything I could recognize offhand yet, and it doesn't seem to have emulated the self-tests. Why on Earth not? Big Grin

Thanks to anyone who can help!

Press [EXIT] + [LOG] simultaneously, this launches the self-test. Then press [<-], then [ENTER] repeatedly to cycle through various component and LCD segment tests; eventually they will all be cycled on/off, including the BAT indicator. When done, press [EXIT] + [Square-Root] to exit the diagnostics and do a machine RESET (but this does not erase memory).

--Bob Prosperi
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10-09-2019, 07:52 PM
Post: #4
RE: HP-42S LCD details
(10-09-2019 06:56 AM)Thomas Okken Wrote:  You're familiar with the 131x16 pixel dot-matrix part; the only other parts are the seven status annunciators. In order from left to right, they are ▼▲, Shift, Printer, Busy, Low Battery, G, and RAD. Out of all these, only the Low Battery annunciator is a bit of a pain in the rear to test, due to the absence of the aforementioned test instruction. You actually have to run down the battery for it to turn on.

To see all seven with their relative positions, take a look at a skin like Erik Ehrling's large 42S, https://thomasokken.com/free42/skins/des...ng42sl.gif along the bottom.

Thanks so much Thomas! That exactly what I wanted to see/know.

Georgia, USA
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10-10-2019, 03:31 PM
Post: #5
RE: HP-42S LCD details
For comparison, here's a photo of a 42S during the self-test step with all anunciators active. Note that the "G" and "RAD" are two separate elements that can be activated independently.

https://i.imgur.com/Xy9Qriz.jpg
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