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Texas Instruments SS-2000 8K CONSTANT MEMORY RAM EXPANSION Cartridge

Date of introduction:	1983	Display technology:
New price:	$99.95 (MSRP 1983)	Display size:
Size:	2.1" x 2.0" x 0.55" 53 x 52 x 14 mm³
Weight:	1.2 ounces, 32 grams	Serial No:	0048508
Batteries:	CR2420	Date of manufacture:	wk 02 year 1984
AC-Adapter:		Origin of manufacture:	USA (LTA)
Precision:		Integrated circuits:	2*HM6264LP
Memories:
Program steps:		Courtesy of:	Joerg Woerner
		Download manual:	(US: 4.2 MByte)

The SS-2000 8K CONSTANT MEMORY RAM EXPANSION Cartridge was developed by Texas Instruments for its CC-40 Compact Computer System and increases its power and versatility by increasing the memory capacity of the computer. The additional memory provided by the 8K RAM cartridge can be used to expand the total amount of memory available for BASIC programs and data storage, or to increase the amount of memory available for machine language programs.

When using the 8K RAM cartridge to expand the memory of the Compact Computer 40 with a standard resident RAM of 6k Bytes, the total amount of memory available for BASIC programs is 14k Bytes.

Dismantling this 8K CONSTANT MEMORY RAM EXPANSION Cartridge manufactured in January 1984 by Texas Instruments in their Lubbock, Texas facility, reveals a small printed circuit board (PCB) with one HN6264L RAM (Random Access Memory) manufactured by Hitachi, Japan and a CR2420 Lithium battery for its backup - hence the Texas Instruments CONSTANT MEMORY phrase.

The HM6264LP uses a CMOS process resulting in a very low power standby consumption of 0.01 mW and features a capacity of 8k Bytes with an access time of just 120 ns. The nominal battery capacity of the CR2420 Lithium battery is 135 mAh, the typical standby current of the RAM about 2 µA for an expected backup time of more than 5 years.

If you have additions to the above article please email: joerg@datamath.org.