Re: A86: Re: Simple Routine Help

To: assembly-86@lists.ticalc.org
Subject: Re: A86: Re: Simple Routine Help
From: Jkhum98@aol.com
Date: Wed, 2 Jun 1999 20:33:06 EDT
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Delivered-To: assembly-86@lists.ticalc.org
Reply-To: assembly-86@lists.ticalc.org


In a message dated 99-06-02 19:49:43 EDT, you write:

> I haven't personally seen the difference, but Mardell or someone else said
>  you need at least a couple of NOP's in between the in and out (can't have
>  too much time, but at least a couple of cycles to give the hardware a 
chance
>  to respond).  And besides what Jeremy said, if you are disabling interrupts
>  or writing your own handler, you need to do a <ld a,$ff \ out (1),a> to
>  reset the port in your main loop or int handler.  If you don't, the calc
>  will give you phantom key presses (very strange).

Yeah, I do reset the port with $FF in the subroutine "Direct_Input", so that 
is done every read from the port.  Linus from the A83 list told me the keys 
will "bounce" and that it is a hardware defect, what does that mean? So you 
think I should put a Halt in between the IN and OUT, and that should do 
it...? Well ok, I'll see if that works, thanks...

Jason_K

Follow-Ups:

Re: A86: Re: Simple Routine Help

From: "David Phillips" <david@acz.org>