Backup of M-Systems DiskOnChip flash with Minipro - Page 1
Forum section: electronics / projects

author: Aiy
author_rank: Regular Contributor
timestamp: August 09, 2023, 08:44:16 pm
content: Hi Everyone,Just as the topic subject suggests, I'd like to backup an old flash by M-Systems.The IC is a DiskOnChip MD-2800-D08 - 8MB Single Chip Flash Disk. Datasheet:https://www.mikrocontroller.net/attachment/51460/DiskOnChip_Mil._DS_Rev2.1.pdfThe datasheet states that it is "Compatible with standard EEPROM pin-out", so I thought it is an excellent candidate for me to get myself a Minipro TL866 and back it up, and perhaps obtain a replacement in case the flash should fail (might as well tape it to the inside of the machine for safe keeping).Although, I've not been able to find the IC on any compatibility list for the Minipro.Does anybody have any experience with reading / writing these chips?Best regards,AIY

author: coromonadalix
author_rank: Super Contributor
timestamp: August 09, 2023, 09:13:43 pm
content: some infos ?http://www.digital-circuitry.com/MyLAB_IC_PROG_DISKONCHIP.htmhttps://hackaday.com/2018/03/30/a-retrocomputer-disk-on-a-chip/https://digicoolthings.com/eprom-programmer-adapter-for-27c400800160-and-27c322-16bit-eproms/last link explanationTL866 support 27C4096 4Mb (JEDEC pin-out) EPROM. Programming is completed in 4Mb banksMeaning the maximum size for the tl866 is 4mb, without an adapter, you will need an programmer who go beyond those 4mba project herehttps://mousebitelabs.com/2019/09/02/27c322-160-programming-adapter/and finallyhttps://github.com/mafe72/27c160-tl866-adapter

author: amyk
author_rank: Super Contributor
timestamp: August 10, 2023, 04:33:11 am
content: This is not a regular flash/EEPROM, and as its name implies, it's more like an SSD, and by virtue of appearing as an MMIO peripheral to the host system, is actually similar to an NVMe SSD in principle. Thus regular multi-chip programmers like the '866 are unlikely to be able to read and write to it. That said, the first link above has plenty of documentation and software to be able to come up with something on your own.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 10, 2023, 11:42:31 am
content: if it really act as an hdd drive, you should be able to copy the contents ??is it an embedded computer ?or something else with this chip on it ?

author: Shonky
author_rank: Frequent Contributor
timestamp: August 10, 2023, 09:49:17 pm
content: Quote from: coromonadalix on August 10, 2023, 11:42:31 amIt's not a hard drive and it's not a regular memory device.Most of the links you posted are based around adapters to overcome the number of pins available on the programmer. Otherwise those devices are just big "regular" memory devices.These things appear more like 8kB memory devices. They only have 13 address lines and 8 data lines. A TL866/T48/T56 hardware wise would be perfectly capable of reading and programming them.So there's a 8kB window a programmer can see. And a regular programmer could probably read that as is - it's likely compatible with a smaller device. To read/write the whole device though, commands need to be sent to move the window around.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 11, 2023, 12:20:04 pm
content: i think you meant 8 meg not 8 k devicestl866 can't go higher than 4mb devices, havent seen bigger model on v6.85 i have, i have ordered some Ebay adapters of one of the previous links

author: amyk
author_rank: Super Contributor
timestamp: August 11, 2023, 01:41:27 pm
content: It's connected to the host system in the same way as 8k of memory. However, that 8k range is occupied by a data window and controller registers.

author: Shonky
author_rank: Frequent Contributor
timestamp: August 11, 2023, 09:54:41 pm
content: Quote from: coromonadalix on August 11, 2023, 12:20:04 pmNo I mean an 8kB *window* like I said. You can't see the whole device at once. There are only 13 address lines ie 8kB.TL866 can go bigger with those adapters. You just read the devices in multiple banks with multiple read and those adapters allow that.With all due respect you should try and read some of the links you found on Google before you comment.