Re: LZ: Now that the battery problem is settled...
[Prev][Next][Index][Thread]
Re: LZ: Now that the battery problem is settled...
> Actually, that's not it. Maybe kinda, but not _exactly_. As was
> mentioned in the earlier posting, when the Z80 reaches a HALT
> instruction, it pulls its /HALT pin (output) low, which then activates a
> circuit that enables the button cell. The reason the calc resets when
> you press [ON] with the AAAs out is because there _is_ a tiny remaining
> charge in a capicator which keeps the RAM and Z80 on. When you _do_
> press [ON], the HALT instruction is no longer active; the /HALT pin on
> the Z80 then goes high again, disabling the button cell. When this
> happens, the calc expects the AAAs to be there, but they're not...
> Now do you see what's happening?
Incorrect. What I'm talking about has NOTHING to do with the Z80 and never
involves the processor at all. It's hard-wired.
>> In order to reset your TI85 (all ROM versions, I don't know about other
>> calculators), all you need to do is REMOVE ONE AAA BATTERY AND
>> PRESS [ON] 10 TIMES. This will _ALWAYS_ work because it's
>> hard-wired to the board and cannot "crash".
Follow-Ups: