User guide

Purchasing additional memory modules
SIMM Technical Specification
Signal Loading Data
Address Bus max 128 pF
WE max 140 pF
RAS / CAS max 59 pF
Data Bus I/0 max 29 pF
Maximum Physical Dimensions
Height no greater than 36.2 mm
Width no greater than 108 mm
Thickness no greater than 9.4 mm
Dynamic Memory (DRAM) Devices
Suitable SIMMs must use square array memory technology, i.e.
Dynamic RAM devices with the same number of rows and columns.
The modules must also support 'Fast Page Mode' and 'CAS before
RAS refresh'.
liming Data
Access time from RAS (tRAC) Access
time from CAS (tCAC) Refresh period
for 1024 cycles (tREF)
* 15 ns preferred for Access time from CAS.
Pinout
max 70 ns
max 20 ns *
max 16 ms
The following pins are unconnected: 11, 46, 48, 66, 71. The ID code
on pins 67, 68, 69 & 70 is not used and therefore irrelevant.
However, non-standard SIMMs with five or more ID pins should not
be used. Pin 29 (unconnected on some SIMMs) carries address bit
11 and a module may only use this for address bit 11.
12