Re: PET 2001 Fix....WAS: Will pay good money for NON working PET 2001 motherboard.

From: William Levak <wlevak_at_sdf.lonestar.org>
Date: Tue, 10 Nov 2009 06:16:36 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.0911100603330.25472@sdf.lonestar.org>
On Mon, 9 Nov 2009, Philip Lord wrote:

> Seems that all the inputs are pulsing except 9 and 10 which are at 0V. All 
> the outputs seem to be at 0V.
> I downloaded the 2316 datasheet and looking that the truth table:
>
> if CE = Low, WE = Hi and OE = Low, then the mode is READ, Output is ACTIVE, 
> and power is ACTIVE.
>
> Unfortunately I don't actually know what all that means :-(

It means the 2316 is being read.  Since it is being used as a character 
ROM, that is normal.  Pins 9 and 10 being low would mean you are not 
changing the 2 low bits of the character.  That would mean that if you 
typed d, e, f, and g, the output would all be the same.  Alternatively, 
the signal could be changing so fast your probe cannot see it.


wlevak@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org

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Received on 2009-11-10 07:00:03

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