blark/a500plus-chipram-expansion

A 1MB chip RAM expansion for the A500+

a500plus-chipram-expansion

This is a 1MB chip RAM expansion designed for the Amiga 500+ in KiCad.

It is in the experimental phase, but I've assembled it and it appears to be working great. However, you've been warned!

Features

Small (42mmx52mm), simple design using only a 40 pin (2x20) female 2.54mm connector. The remaining pins are for the RTC which is on-board the A500+, so they are unecessary for RAM expansion. This makes it possible to use a 40 pin connector, which is cheaper and easier to find.

WARNING: make sure you plug it in correctly see the install section below.

Schematic

A PDF file of the schematic can be found in this repo.

Ordering

I shared the design at Oshpark

BOM

Designator	Description
J1	40P (20x2) female header 2.54mm
J2	1x DPDT Sub-Miniature Slide switch (9x4x3.5mm, easily found on Ebay)
U1-U2	IS41C16257-35T 4mbit DRAM (256 x 16)
C1-C6	100nF 603 SMD capacitor
C7	10uF 805 SMD capacitor
R1	10K 805 SMD resistor

Install

Be careful during install to match pin 1 on the expansion with pin 1 on the A500+ memory expansion port! Here's an image of how it should be installed:

Thanks

The parts library I've included (and expanded upon) in this repo is "borrowed" from Kai Robinson check out his great projects!

a500plus-chipram-expansion's Issues

Different chip

I love this design but the chips used are a bit obscure. Big ask, could it be redesigned to use a more commonly available chip?

PRETTY PLEASE :D