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
What ROM have you been smoking? At 66 is simply skips the user int routine,
leading someone like me to believe that hey,
NMI's are a possibility. One would assume an ON key interrupt would be an
NMI. But when you do this it wouldnt crash, right?
di
halt
Well it does. An NMI would be executed no matter what, skipping the di
ignoring the halt and interrupting at any time. NMI just
complicates hardware.. just disassembling the rom you can tell that TI
wanted to save time and keep things pretty simple. They also seem to want
the calc really stable too, with all those checksums.
>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
>IRC/AIM:Kupopo
>Hopemage:http://www.mindspring.com/~shicks/
>
>
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