SIMM-RAM

Arduino library for interfacing SIMM RAM chips (GM71S4400C, AAA4M304J, etc.) with an ATmega328P

It will give you extra RAM to store and restore dynamic data in your sketches. You can read-write to memory very fast.

Library support only 4bit databus chips (most simm chips use 4 bit data bus)
Support 8 or 10 bit address bus and can address total 512kb memory.
8 bit adress bus work very fast, 10 bit little slow.
Support normal and EDO mode read-write.
You cant use Arduino internal serial interface due RAM-IO reading\writing.

Sketch for chip ram-tests included ( ram_test.ino ).

Install.

Copy "libraries\simm-ram" folder to Arduino libraries path.

Usage.

In folder with you sketch you need to create file named ram_config.h that contain RAM chip config. By default library use RAM_ADDRESS_BUS_8B means 8 bit address bus. Example:

#ifndef RAMCONFIG_H
#define RAMCONFIG_H
// This example is application RAM chip(s) config

// Define your memory chip addressbus size RAM_ADDRESS_BUS_8B or RAM_ADDRESS_BUS_10B
//#define RAM_ADDRESS_BUS_10B

#endif

For full example look to sketch ram_test.ino and RAMALGA project (ram logic analyzer).

Connection:

Thanks to

Dmitry Grinberg http://dmitry.gr/index.php?r=05.Projects&proj=07.%20Linux%20on%208bit
Alexandre Rouma https://github.com/AlexandreRouma/SIMM
Rafael Ignacio Zurita rafaelignacio.zurita@gmail.com for original example https://github.com/zrafa/30pin-simm-ram-arduino/
André Fachat http://6502.org/users/andre/icaphw/design.html#dram

Used docs:

datasheet IMM_RAM_GM71S4400C.PDF http://www.pjrc.com/mp3/simm/datasheet.html http://www.pjrc.com/mp3/simm/simm.html