TI-99 32K expansion

The most common TI-99/4A 32K RAM chip is the 28 pin AS6C62256 RAM chip.  Any solution I look at will likely use this chip.

The exact spec is 32k Ram AS6C62256-55PCN 28DIP 0.6″.  It is a 32kx8 memory array chip which was very common, but not when the TI-99/4A was released.  Texas Instruments used a totally different configuration.  Below has the pin description. 

All the additional pieces you will need for a TIPI setup. 

SN74HCT245N IC TXRX NON-INVERT 5.5V 20DIP

CD74HCT21E IC GATE AND 2CH 4-INP 14DIP

SN74HCT138N IC DECODER/DEMUX 1X3:8 16DIP

2N3904BU Transistor NPN 40V 0.2A TO92-3

ICS-314-T 0.3″ IC SOCKET, DIP, 14P 2.54MM

ICS-316-T 0.3″ IC SOCKET, DIP, 16P 2.54MM

ICS-320-T 0.3″ IC SOCKET, DIP, 20P 2.54MM

ICS-628-T 0.6″ IC SOCKET, DIP, 28P 2.54MM

CONN EDGE DUAL FMALE 44POS 0.100 395-044-524-202 (Requires Modification)

44 PIN (Two Row 22PIN 2.54mm Pin Header) (Made with Smaller pieces)

3 PIN 2.54mm Pin Header (For Power Jumper)

2.54mm Jumper

DC 2.1×5.5mm power jack

3mm RED LED

680 Ohm 1/4W Resistor

2 ) 1k Ohm 1/4W Resistors

10k Ohm 1/4W Resistor

4 ) 0.1uf (104) capacitors

2.54mm Round Female Socket Pin Header Strip (88Pins are required)