Re: CBM softwarez - let's solve the soft-rom mystery.

From: Nils Eilers <nils.eilers_at_gmx.de>
Date: Mon, 5 Mar 2018 15:14:14 +0100
Message-Id: <20180305151414.99d98a3e036e512dcf1bb028@gmx.de>
On Sun, 4 Mar 2018 17:14:34 -0700 (MST)
Tonguc Endem <calculathor@hotmail.com> wrote:

> Do you know the significance of poking address 634 as I've explained in my
> example?
> If I understood correctly, Nils' site mentions that controlling write
> protect should be possible with a poke. 
> I'm thinking maybe that's what this program is trying to do so you wouldn't
> even have to set the switches manually?
> There has to be a way to connect the write protect status and it's control
> to address 634.

Address 634 is located somewhere in RAM, in the BASIC program area. This doesn't sound like a universal address to be used with all sorts of software.

With my SoftROM hardware, a write protection can get enabled if and only if a 28C64 EEPROM chip is used. It doesn't work with a 6226 or 48Z08 RAM chip, these require manual switches.
The 28C64 EEPROM is (un)locked with a special sequence of accesses, have a look at the datasheet for details:

http://ww1.microchip.com/downloads/en/DeviceDoc/doc0270.pdf#G1054916



On Mon, 5 Mar 2018 00:05:33 +0000 (UTC)
Steve Gray <sjgray@rogers.com> wrote:

> Is this board available for purchase somewhere?
I've still got a whole bunch of unpopulated boards here, for 0,99 € each. Just drop me a line to nils.eilers@gmx.de and let me know how many boards you'd like and the postal address.

BTW: I also got some surplus boards of my Shrinked SuperPET prototype board for 3 € per pcb. It upgrades a 8032 board to a SuperPET and is based on a CPLD.

Nils


-- 
Nils Eilers <nils.eilers@gmx.de>, http://petsd.net
PGP Fingerprint: D174 DD43 1F72 CAEC 9741 771C ABC3 CA50 C90B E483

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Received on 2018-03-05 16:00:03

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