DRAMS: Difference between revisions
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Latest revision as of 10:10, 9 September 2018
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 |
1 ° 16 |
GND (0V) |
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 |
1 ° 16 |
GND (0V) |
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 |
1 ° 16 |
GND (0V) |
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 |
1 ° 18 |
GND (0V) |