DRAMS

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DRAMS

Dynamic Random Access Memories used in ZX Spectrum machines.

4116

16Kx1 bit DRAM chip

8 of this IC make the lower 16k part of the ZX Spectrum 16K/48K RAM.

e.g. NEC D416C-2

Pinout:

(-5V) VEE
DIN
WE
RAS
A0
A2
A1
(+12V) VDD

1 °     16
2       15
3       14
4       13
5       12
6       11
7       10
8        9

GND (0V)
CAS
DOUT
A6
A3
A4
A5
VCC (+5V)

4532

32Kx1 bit DRAM chip

The addressing logic uses 8 line (A0 to A7) for row address (RAS) and 7 line (A0 to A6) for column address (CAS). At CAS the A7 line has to be fixed at logic 0 or 1 depending on chip type.

8 of this IC make the upper 32k part of the ZX Spectrum 48K RAM.

e.g: TI TMS4532-20NL3 or OKI M3732-L TI TMS4532-20NL4 or OKI M3732-H

Pinout:

NC
DIN
WE
RAS
A0
A2
A1
(+5V) VCC

1 °     16
2       15
3       14
4       13
5       12
6       11
7       10
8        9

GND (0V)
CAS
DOUT
A6
A3
A4
A5
A7

A7 should set logical 0 at CAS for TI TMS4532-20NL3 and OKI M3732-L chips, and logical 1 for TI TMS4532-20NL4 and OKI M3732-H chips.

The A7 line is omitted for refresh address.

4164

64Kx1 bit DRAM chip

16 of this IC make the 128K RAM of the ZX Spectrum 128K and ZX Spectrum +2 (except ZX Spectrum +2A/2B).

e.g:NEC D4164C-3

Pinout:

NC
DIN
WE
RAS
A0
A2
A1
(+5V) VCC

1 °     16
2       15
3       14
4       13
5       12
6       11
7       10
8        9

GND (0V)
CAS
DOUT
A6
A3
A4
A5
A7

4464

64Kx4 bit DRAM chip

4 of this IC make the 128K RAM of the ZX Spectrum +2A/2B, +3/3B.

e.g:MICRON MT4067-15

Pinout:

OE
DQ1
DQ2
WE
RAS
A6
A5
A4
(+5V) VCC

1 °     18
2       17
3       16
4       15
5       14
6       13
7       12
8       11
9       10

GND (0V)
DQ4
CAS
DQ3
A0
A1
A2
A3
A7