9
3.
System Memory
The system memory of the NPC-486E consists of two 72-pin SIMM style DRAM
modules. A SIMM module is standard sized printed circuit board containing memory
chips.
3.1
Physical Configurations
There are two SIMM memory sockets on the NPC-486E.
SIMM specifications are 72 pin, 36 bits wide, single-sided, 70 Ns. Single sided is
important since the SIMMs are inserted at an angle to maintain a low profile. This
prevents double sided (chips on both sides) from working well. Adastra also recommends
that memory with gold leads be used. The SIMM sockets have gold contacts and using
gold leaded SIMMs will improve long term reliability. These may be obtained from
Adastra or at local computer stores and are often referred to as PS/2 style memory
modules. Compatible modules come in 256Kx36 (1M), 512Kx36 (2M), 1Mx36 (4M),
2Mx36 (8M), and 4Mx36 (16M) capacity. The resulting memory configurations are 1M,
2M, 4M, 8M, 16M, or 32M bytes. One or two SIMMs may be loaded. If only one is
loaded, either socket may be used.
E27
E28
Bank 0
Bank 1
E18
J1
1
1
J19
U6
U7
E9
U13
2
J2
J3
E5
U8
E8
E7
E6
2
J4
1
6
E16
E10
E14
E13
E11
E15
E12
U9
E17
U14
1
E1
J18
1
E3
E2
E4
3
E19
E20
E21
E22
E23
E24
E25
U15
U16
U10
E26
U11
SIMMs
1
J6
J7
J8
J5
1
1
J9
J10
U24
E29
BT1
E30
1
J11
U18
1
J12
1
E31
E32
U21
T1
J17
1
J14
J13
1
J16
1
Содержание NPC-486E
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