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
At 06:07 AM 5/29/98 -0400, you wrote:
>
>>No, the [ON] interrupt is an NMI (non-maskable interrupt). It
>>cannot be shut off. It is written on the circuit board. In fact,
>>because of this, you will never have to pull all 5 batteries
>>unless sqrtON (or whatever the user [ON] interrupt handler is)
>>is corrupted.
>
>It is not an NMI. Someone please back me up at this. If it was, the shutdown
>routines would have a di and a halt statement. The NMI would get through the
>di. Where is it written on the circuit board? You can STILL hard lock the
>calculator, and there is NO sqrtON handler.
>
>You dont believe me? Try this
>
>di
>halt
>ret
Yes, and since it does, you don't need the ret.
>
>Now DI doesnt affect an NMI so if the ON key was really an NMI then this
>wouldnt lock the calc. When the ON key was pressed, it would call the
>interrupt, come back, and return to the system. If this code doesnt crash,
>tell me, but then I will really really be suprised
>
>I disassembled the ROM, the interrupt handler is fixed in the code, it makes
>a jump to the ON key interrupt handler routine. I did over 5 hours of
>disassebling and came to the conclusion there are no NMI's.. I have been
>reading some of the messages about interrupts by Jimmy Mardell and he also
>says "The TI-8x doesn't have any NMI's" and someone (maybe him) also says
>they haven't even seen a computer with an NMI
>
>Later,
> Matt
>
>
// David Phillips
// mailto:electrum@tfs.net
// AIM: electrum32
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