Re: 4032 ROM add-on

From: Hans Liss <Hans_at_Liss.pp.se>
Date: Sat, 1 Jun 2019 09:20:40 +0200
Message-ID: <e10f78df-1b8f-fa2d-00dd-b5b9054ff521_at_Liss.pp.se>
A little more, based on calls to $ffd2:

At $90f8, it prints out "{Return}OFF{Return}"
At $95d7, it prints out a given text within quotes
Around $9a43, it prints out bytes from the block around $9af7, but in a
convoluted way. Probably need to test-run that code to see what it does.

/Hans

On 2019-06-01 00:15, Hans Liss wrote:
> I started disassembling it and found very little. Not knowing enough
> about the PET is a bit of a problem. :)
>
> Still, there's code at $95fd that resembles a simple one-letter command
> handler for commands like 'A', 'D', 'O', 'T', 'S', 'R', 'H','V','M','N'.
>
> Also, at $92a4, there's a string containing 'CLR<Return>', which is
> loaded by a routine at $9280 and used for who knows what, possibly
> pushed onto an input queue or something like that.
>
> I thought it might be a machine code monitor but I haven't found any ROM
> images online that resemble this one - not even a little.
>
> /Hans
>
> On 2019-05-31 15:38, Francesco Messineo wrote:
>> Hi all,
>> I'm repairing a 2001N-32 that has Basic 4.0 upgrade (all EPROMs
>> instead of ROMs).
>> I've also found an additional ROM in the $9000 socket, the only string
>> that seems to be in the image is "BASIC 4.5". I've attached the ROM
>> dump, does anyone know what it is and how to activate it?
>> Thanks


Received on 2020-05-29 21:58:59

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