RAM part numbers & external mem interface

[PICoHolic]

Hello,

Any suggestions for external RAM part numbers to be used with the external memory interface of 80-pin PIC devices?

Thanks

[PCM programmer]

I've never used external RAM, but I'll try to help.

Look at the CCS page for their 18F8722 board.
http://www.ccsinfo.com/product_info.php?cPath=Store&products_id=18F8722kit
You can click on the board for a zoomed photo. It shows two SRAMs
from ST Microelectronics, p/n M68AF031A, 70ns access time.
Here's the data sheet:
http://www.datasheetcatalog.org/datasheet/stmicroelectronics/8668.pdf
The CCS board runs at +5v, so they use 5v SRAM chips (not 3.3v).

The exercise book has schematics that show how to connect the SRAM
chips to the latches and the PIC:
http://www.ccsinfo.com/pdfs/Development_Kit_for_the_18F8722_Exercise_Book.pdf

I don't think ST Microelectronics makes those SRAMs anymore. So a
cross-reference part is needed. Cypress makes Async SRAMs.

If you search at Digikey for: SRAM Asynchronous
http://www.digikey.com
Then select this size: (256K) 32K x 8 and this type: SRAM Asynchronous
Also select these two voltage ranges: 4.5-5.5 and 4.75-5.25
Then click Apply Filters. You will get several chips from Cypress and
ISSI, with speeds ranging from 12ns to 45ns.
The pinouts are not identical between the Cypress and ISSI chips.