[Coco] 128K EEPROM Cartridge board

[Chad H]

Actually, upon closer inspection the datasheet, it looks like it has onboard software data protection that can be turned on or off by a 3 byte code sent to the chip.  This would negate the need for the write-protect jumper.  If we had a program on the CoCo to write to the chip, it could send the bytes to unlock the chip, write the ROM image, then send the bytes again to lock it back down.

-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Mark J. Blair
Sent: Sunday, January 25, 2015 10:52 AM
To: CoCoList Computer Enthusiasts
Subject: Re: [Coco] 128K EEPROM Cartridge board


> On Jan 25, 2015, at 08:28, Chad H <chadbh74 at hotmail.com> wrote:
> I have the idea of revamping the 2764-27512 EPROM boards I've been building, removing the existing DIP layouts and adding the option to mount either the DIP or PLCC version of the 29EE010.  I would also need to add one additional jumper for the A16 address line.  This would give more capacity for roms , each selectable by jumpers...

These EEPROMs should also be writable in place in the CoCo, without needing any external programmer at all, if I'm not mistaken! I'd include a jumper and pull-up resistor on the write enable line in order to write-protect the memory.


-- 
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/


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