DRAMS: Difference between revisions
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64Kx1 bit DRAM chip | 64Kx1 bit DRAM chip | ||
16 of this IC make the 128K RAM of the [[ZX Spectrum 128K]] and [[ZX Spectrum +2]]. | 16 of this IC make the 128K RAM of the [[ZX Spectrum 128K]] and [[ZX Spectrum +2]] (except [[ZX Spectrum +2A/2B, +3/3B|ZX Spectrum +2A/2B]]). | ||
e.g:NEC D4164C-3 | e.g:NEC D4164C-3 |
Revision as of 18:19, 17 October 2016
DRAMS
Dynamic Random Access Memories used in ZX Sopectrum 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) |