Now I can get OTP (One Time Programmable) 512K EPROMS by Microchip/Atmel for about $2.50 in single quantities, and they are in current production. But being a one time programmable device means that you better get it right the first time, and be happy with it forever. However unless you plan on investing in a chip programmer such as the TL866 Plus, this may not be many peoples cup of tea. Luckily for the 576NUC+ there really is no need, since The Brewing Academy will be selling them with pre-programmed ROMs when they go into production.
The 576NUC+ system ROM contains two different Operating Systems, two versions of BASIC, and two games. It could be handled by a OTP device as mentioned, and for most people that'll probably be OK. But for a few of you who love to be able to customize your system, a re-flashable ROM would be desirable, hence the reason I was looking for an inexpensive and readily available source of these.
So I went in search for that cheaper EEPROM, once again going back to eBay. This time I found another seller for the SST EEPROMS that was advertising a deal that I knew was too good to be true, but part of me was game to find out for sure since the seller was only asking for about $1.00 a piece.
Here's that eBay listing.
This story has a happy ending...
Thanks to a AtariAge member Mr Robot's sleuthing skills, he matched the FAKE chip ID to a Winbond W27C512 EEPROM. And when I plugged those parameters into the XG Pro TL866 Plus programming app, everything fell into place allowing me to do multiple re-flashes of the chip as seen below.
BTW, I was able to flash all 20 chips successfully as Winbond W27C512's.
However even though in the end this will work for what I need, I can't in my right mind recommend ordering from this seller without at least verifying what the heck is going on, although it's probably a case of Cha Bu Duo (aka: "close enough" - thanks to Mr Robot for that bit of insight). I won't be posting a link to that eBay auction, and I won't change the title of this blog post either, since it really is a fake, or in other words a substitution of another chip meant to fake the characteristics of the one it replaces..