Date   : Sat, 11 Feb 2006 13:55:45 -0000
From   : "neil f" <faz@...>
Subject: FW: B+ 64k won't respond to keyboard, Econet fitted

 

> -----Original Message-----
> From: Majordomo List Manager [mailto:majordomo@...] On
Behalf 
> Of Sprow
> Sent: Saturday, February 11, 2006 10:20 AM
> To: bbc-micro@...
> Subject: Re: [BBC-Micro] B+ 64k won't respond to keyboard, Econet 
> fitted
> 
> In article <060209235502@...>,
>    Jonathan Graham Harston <jgh@...> wrote:
> 
> > > It started out with the 'no clock' message, and showed no
> response
> > > to key presses, so I pulled the 68B45 chip. Now it just
> says Acorn
> > > OS
> >  
> > Removing the 6854 wouldn't change keyboard behavior.
> 
> If the reason for not getting to the ">" prompt was that NFS was 
> waiting for a clock, then this would have the symptom of non working

> keyboard.

Sorry, should have made clear that I do have the normal >_ prompt.
Everthing looks normal except that there's no response to keypresses
(bar Break and Ctrl/Break).

> 
> Removing the 68B54 should make NFS dormant, thus making the keyboard

> work, if that's the fault.
> 
> On 09 Feb, neil f <faz@...> wrote:
> > It's interesting that delete/Break is recognised and
> responded to on
> > this B+ while single keypresses are ignored. I'm guessing Break
has 
> > its own interupt line and isn't scanned in the normal way.
> When Break
> > is registered, though, the system must check to see what
> other key is
> > pressed and respond accordingly. That must involve a
> keyboard scan, so
> > something must be working in that area. From the above you
> can gather
> > that changing file systems doesn't seem the make the system
> respond to
> > keypresses.
> 
> Break is a "special" key in that it yanks the processor reset line 
> directly, however you don't mention specifically what happens when 
> this is done. Just that it is responded to - what does the screen
say?
> Sprow.

When I press Break, the "32K" disappears from the title. Crtl/Break
restores it. Delete/Break changes file system as normal according to
the title message. So it seems Break+key combinations are recognised
and acted on correctly, but no other keypresses get any response on
screen. I'm loath to start clipping the legs off the 6522 chips to
unsolder and replace them, but maybe that's the only option left. I've
substituted keyboards and cables and run with no ROMs at all other
than OS but the result never varies: the ">_" prompt just sits there
waiting with the underline flashing as normal.

-Neil.


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