Re: A86: Questions on Port 3, calc on, off, APD, etc
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Re: A86: Questions on Port 3, calc on, off, APD, etc
In a message dated 98-05-27 21:49:24 EDT, you write:
<< Hey this is Matt. I have been disassembling the ROM and I have a few
questions
1.) Does anyone have any details on Port 3? Does it operate on bits, or does
it recognize bytes themselves at different
instructions? Why does so many Rom routines write two bytes to them? These
are written to Port 3 often - $00 $01
$09 $0B, $0A $0B. I read the latter were that $09 for the ON key being off,
$0A for the on key being on
2.) What exactly is an ON interrupt vs. ON key pressed and a timer interrupt
vs. whether timer has occured. These are some of the bits read. Can an ON
interrupt occur without the ON key being pressed? The rom seems to check for
that possibility. How are the bits that you write relate to the bits that
you read?
3.) When the calculator is off, does the interrupts run in the background or
does it disable timer interrupts and wait for an ON interrupt. Does anyone
have any details on this?
4.) The calculator appears to turn on immediately when you put batteries in
it, executes a HALT and waits for the ON key before it initializes. Is this
correct?
Yes, that is correct.
5.) Does the calculator do different things if it is shut off depending on
whether it what caused by the APD shut it off or [2nd][ON]. It appears to
have a difference
yes, it doesn't flush the menu's + return to the home screen w/ APD
Anyone have any idea? Dan Eble? Jimmy Mardell? Trent Lillehaugen? Anyone?
>>