[A83] Re: self test counting

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: self test counting
From: Tijl Coosemans <tijl.coosemans@mail.be>
Date: Fri, 14 Sep 2001 16:36:03 +0200
Reply-To: assembly-83@lists.ticalc.org

Well, since I didn't had much to do, I ran a few tests.

When you press enter at the 'Enter self test' screen, the calculator makes a one-byte checksum of the rom-pages (not 0000h-3FFFh). It adds up all bytes on every page. On my calculator the checksum was 00h, which is probably different on other calculators. If the number doesn't fit, then you get a ROM FAIL message. Whatever key you press then, the calc will reset and show a mem cleared message. (Maybe this is a good way to figure out if you have a bad rom dump or not.)

Next thing what happens is, that the ram area at 88A4h-FFFFh is filled with 00h->FAh,00h->FAh,... And then it checks if each byte is still the same. If it isn't you get a RAM FAIL message, press a button, mem cleared. The reason it doesn't have problems with the stack is because that was moved to 88A4h. (The ram addresses may be different on other calculators.)

After that it checks for an ON-key press by checking an IY bit. If there wasn't it increases a counter, displays it and does everything all over again. So the counter indicates how many times it has checked both rom and ram.

If you press ON, the calculator runs an LCD test. Each time you press a key you get a different screen in the following order: vertical bars, black screen, white screen, diagonal lines, horizontal bars. Then you get vertical bars again and the contrast is set to maximum. Each time you then press a key the contrast is lowered until it reaches 0. You can also skip this LCD test by pressing ON at whatever screen.

Screen is cleared and the contrast is restored to what it was, before the lcd test.

Next and last test is a keyboard test. You get a number on the screen that indicates the key you have to press. The number is the same as what the Basic command getKey returns. So the first digit indicates the row and the second the column. Each time you press the right key the number changes. This test can also be skipped by pressing ON. You then just quit and get a Mem cleared message.

When all test succeeded the calculator displays "OK", which is rather funny :-)


> ----------------------------------------
> From: The one and only SUCKER ... <sucker_pvn@hotmail.com>
> Sent: Thu Sep 13 19:37:06 GMT+02:00 2001
> To: <assembly-83@lists.ticalc.org>
> Subject: [A83] self test counting
> 
> 
> 
> Somebody knows where the counter from MODE-ALPHA-S stops?
> Or maybe describe what is does??
> 
>      SUCKER
> 
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
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