DRAMS: Difference between revisions
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16Kx1 bit DRAM chip | 16Kx1 bit DRAM chip | ||
8 of this IC make the lower 16k part of the ZX | 8 of this IC make the lower 16k part of the [[ZX Spectrum 16K/48K]] RAM. | ||
e.g. NEC D416C-2 | e.g. NEC D416C-2 | ||
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The addressing logic uses 8 line (A<sub>0</sub> to A<sub>7</sub>) for row address (RAS) and 7 line (A<sub>0</sub> to A<sub>6</sub>) for column address (CAS). At CAS the A<sub>7</sub> line has to be fixed at logic 0 or 1 depending on chip type. | The addressing logic uses 8 line (A<sub>0</sub> to A<sub>7</sub>) for row address (RAS) and 7 line (A<sub>0</sub> to A<sub>6</sub>) for column address (CAS). At CAS the A<sub>7</sub> 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 | 8 of this IC make the upper 32k part of the [[ZX Spectrum 16K/48K|ZX Spectrum 48K]] RAM. | ||
e.g: | e.g: | ||
Line 95: | Line 95: | ||
64Kx1 bit DRAM chip | 64Kx1 bit DRAM chip | ||
16 of this IC make the 128K RAM of the [[ZX Spectrum 128K]] | 16 of this IC make the 128K RAM of the [[ZX Spectrum 128K]]. | ||
e.g:NEC D4164C-3 | e.g:NEC D4164C-3 |
Revision as of 18:06, 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.
e.g:NEC D4164C-3
Pinout:
NC |
1 ° 16 |
GND (0V) |