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


i can answer probably all of them but i know i can answer 3 and 5 and
get it right. when the calculator is off, interrupts do not run (i tried
making a clock using IM 2 and IM 1 and it didn't work). when you turn it
off manually it takes you back to the home screen, where as w/ APD it
saves your place. i also think that for #4 that you are right...

Matt2000 wrote:
> 
> 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?
> 
> 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
> 
> Anyone have any idea? Dan Eble? Jimmy Mardell? Trent Lillehaugen? Anyone?
> 
> :-)
> 
> Later,
>     Matt

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