Did they ever make a 2364 OTP EPROM - Page 1
Forum section: electronics / general

author: alank2
author_rank: Super Contributor
timestamp: February 11, 2023, 01:48:14 am
content: I've got a NEC PC-6006 RAM/ROM cartridge and found this page about it:https://p6ers-net.translate.goog/mm/pc-6001/dev/4keprom/index.html?_x_tr_sch=http&_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wappI'd love to find an EPROM solution for 8K, but it looks like 8K is pushing it about the number of pins. I'm guessing maybe it was designed for mask ROM 2364, but I wonder what programmable solutions there are.

author: srb1954
author_rank: Super Contributor
timestamp: February 11, 2023, 01:55:06 am
content: Quote from: alank2 on February 11, 2023, 01:48:14 amMotorola made some 8K EPROMs in a 24pin package: MCM68764 and MCM68766.However, both are now as rare as hen's teeth and probably can't be programmed by any modern EPROM programmer.

author: Benta
author_rank: Super Contributor
timestamp: February 11, 2023, 11:53:39 am
content: 27C64 are still to be had.

author: srb1954
author_rank: Super Contributor
timestamp: February 11, 2023, 12:08:43 pm
content: Quote from: Benta on February 11, 2023, 11:53:39 amBut these won't fit into the 24 pin socket in the ROM cartridge the OP is referring to.

author: wraper
author_rank: Unknown
timestamp: February 11, 2023, 12:32:57 pm
content: You can make a PLCC32/DIP28 to DIP24 adaptor board for 2764.

author: Benta
author_rank: Super Contributor
timestamp: February 11, 2023, 08:28:55 pm
content: Quote from: wraper on February 11, 2023, 12:32:57 pmYep. They're actually available (as raw PCBs). That would be my solution as well.

author: edavid
author_rank: Super Contributor
timestamp: February 11, 2023, 08:42:36 pm
content: Quote from: wraper on February 11, 2023, 12:32:57 pmIf you are making a PCB, you might as well use some EEPROM/flash chip in SO28.

author: wraper
author_rank: Unknown
timestamp: February 11, 2023, 09:20:05 pm
content: Quote from: edavid on February 11, 2023, 08:42:36 pmThere will be a problem with re-programming it unless it's in a SO ZIF socket or PCB has additional terminals on the opposite side for programming. As of PLCC/DIP, you can solder a normal socket on PCB and pull IC out for programming.

author: blacksheeplogic
author_rank: Frequent Contributor
timestamp: February 11, 2023, 09:43:11 pm
content: Quote from: srb1954 on February 11, 2023, 01:55:06 amCheap programmers aimed at the hobby market I think is what you meant here. Moden programmers like the Galep 5 series support them, and I think from memory any of the Galep 4's did as well. Conitec I'm sure is not the only modern programmer to support them but they don't compete in the same market as the T56, or RT809H which are very capable for their price but more limited in what they support.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: February 11, 2023, 10:42:45 pm
content: https://www.sellmyretro.com/offer/details/rom-el-_2364-flash-eprom-chips-(replacement-for-2364-rom)-2339?PageSpeed=noscriptFrom the description, this unusual chip did exist.

author: alank2
author_rank: Super Contributor
timestamp: February 13, 2023, 04:15:17 pm
content: Thanks everyone for the information - I was able to get an AM27C256 28-pin hooked up and working as an 8K IC with a bit of solderless wires going into the ZIF and a breadboard. Getting it up to 4K wasn't too hard, and then I figured out what to connect A13 to so it could access 8K properly so I was able to run the extended BASIC Rom extension on the computer.