RE: A86: Hooking interrupt idea
[Prev][Next][Index][Thread]
RE: A86: Hooking interrupt idea
I don't think the processor is executing instructions. The
200-times-per-second interrupts are disabled, and the processor is stuck on
a HALT instruction until ON is pressed. The HALT state puts the processor
into a low power mode.
________________
Jeff Tyrrill
http://tyrrill-ticalc.home.ml.org/
http://ti-philes.home.ml.org/
-----Original Message-----
From: Jimmy Mårdell [SMTP:mja@algonet.se]
Sent: Sunday, November 02, 1997 12:50 AM
To: assembly-86@lists.ticalc.org
Subject: Re: A86: Hooking interrupt idea
Steve86Asm@aol.com wrote:
>
> [About interrupts and the ON key]
>
> Ok. So, you could have code at the address that it jumps to that fixes
the
> conditions so that it doesn't jump. You could then also have code that
would
> exectute at start-up. But how would you set all the memory locations
just
> before the calc shuts down?
I'm not really sure what you mean...
> One more thing.... Are you saying that it jumps to 38H _every_ time ON
is
> pressed, or just if it's off. Also, do the interrupts occur 195-200 /s
even
> when running asm programs? That would mess up the program that's
running,
> wouldn't it?
The CPU is (I think) still executing assembly instructions when you turn
off
the calculator (not when you remove the batteries of course). And yes,
every
time you press the ON key an interrupt occurs (if IFF1=1). Since the
processor
is always active when there are batteries in the calc, there is no
reason to
believe it would treat the ON key different when it's turned off.
The interrupt frequency is a hardware thing and is impossible to change;
ie, asm programs have nothing to do with it.
--
Jimmy Mårdell "The nice thing about standards is that
mailto:mja@algonet.se there are so many of them to choose from."
http://www.algonet.se/~mja
IRC: Yarin "Sanity? I'm sure I have it on tape
somewhere!"
Follow-Ups: