the ATMEL0 AT29C256 chip is the de facto FLASH0-ROM0 chip in use. It uses a 5V programming voltage, can be erased repeatedly electronically. They can be reused many times (about 100,000) without "wearing out." It is not significantly more expensive than OTP0 ROM0s, and can save a lot of time compared to UV-Erase0 chips when many program changes are needed. This is because EPROM0s must be erased in a special ultraviolet eraser device which takes 15-30 minutes, which is another advantage of the flash chips - you don't need a UV eraser! These flash chips are pin-compatible with 27 C2560 chips. Some people have difficulty with the Atmel chips. Another recommended part is SST's 27SF2560 it is also a flash chip (most 27-series chips are UV-Erase only) Sources:

• http://www.moates.net0 (~$5 each)
• http://web.archive.org/web/20161005153313/http://web.archive.org/web/20161005153313/http://www.allamerican.com:80/:80/0 (~$5 each, $50 minimum order)
• https://www.arrow.com0 (~$5 each, no minimum order)
• http://web.archive.org/web/20050211123612/http://progshop.com:80/shop/eproms/0 (70PI <$6 each)

on page 14 of the AMD29C256 Datasheet0, directly after the base part number, the 2 digits are the speed of the ROM0 (90ns; 70, 120 (12) and 150 (15) are also available). Then the first letter: - "J" is PLCC package (square 32-pin package)

• "P" is DIP (this is what you want, unless you're doing your own thing)
• "T" is TSOP

The second letter - operating temp range code: - "C" means commercial and is rated for 0-70C (32F to 158F)

• "I" means industrial and is rated for -40 to 85C (-40F to 185F) If you have a choice, get this one, because it can get very, hot inside your car in the summer.

Note: most OBD00 PR3 and PW0 ECU0s I've seen are very picky about these chips, and frequently throw random solid CEL0s when using them - all speeds, including 90ns. I would advise using other chips in these ECU0s.