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
Well, this is a little late (haven't been paying much attention to the list in
the past 2 weeks - still have 241 messages left to read)... Anyway, if anyone
still doesn't believe that there is no NMI, just disassemble at 66h, where the
Z80 NMI jumps to. You'll find that it is nothing.
0038 08 ex af,af'
0039 d9 exx
003a fdcb2356 bit 2,(iy+$23)
003e 2826 jr z,$0066 ; (38)
0040 3afdd2 ld a,($d2fd)
0043 21fed2 ld hl,$d2fe
0046 96 sub (hl)
0047 2125d3 ld hl,$d325
004a 96 sub (hl)
004b 214dd3 ld hl,$d34d
004e 96 sub (hl)
004f 2175d3 ld hl,$d375
0052 96 sub (hl)
0053 219dd3 ld hl,$d39d
0056 96 sub (hl)
0057 21c5d3 ld hl,$d3c5
005a 96 sub (hl)
005b 2005 jr nz,$0062 ; (5)
005d cdfed2 call $d2fe
0060 1804 jr $0066 ; (4)
0062 fdcb2396 res 2,(iy+$23)
0066 db03 in a,($03)
0068 1f rra
0069 3824 jr c,$008f ; (36)
006b 1f rra
006c 3828 jr c,$0096 ; (40)
006e 1816 jr $0086 ; (22)
0070 fdcb1e76 bit 6,(iy+$1e)
0074 280e jr z,$0084 ; (14)
0076 47 ld b,a
0077 db01 in a,($01)
0079 4f ld c,a
007a 3eff ld a,$ff
007c d301 out ($01),a
007e cb41 bit 0,c
0080 ca5c0c jp z,$0c5c
0083 78 ld a,b
0084 d303 out ($03),a
0086 3e0b ld a,$0b
0088 d303 out ($03),a
008a 08 ex af,af'
008b d9 exx
008c fb ei
008d ed4d reti
It's right in the middle of the intterupt routine!
Matt2000 wrote:
> >> 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
>
> di
> halt
> ret
>
> crashes the calc even if the ON key is pressed. It wont HARD lock the calc
> (meaning you have to take the lithium battery out)
> unless you put this code in the interrupt handler. Let me tell you a few
> things ----
>
> - The TI-86 has no NMI's
> - The ON key interrupt and the timer interrupt are both maskable interrupts
> and are both the same kind of interrupt
>
> There are some weird things that go on, something leads me to believe that
> something other then the ON key produces an
> ON key interrupt. I am doing experiements to find more information on this.
> I am soo close to completing a ROM 1.2 Down-Left bug patch
>
> Later,
> Matt
--
Stephen Hicks
mailto:shicks@mindspring.com
ICQ:5453914
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