Zx spectrum lower ram
About the Zx spectrum lower ram PCB
Zx spectrum lower ram is an open source PCB design by derekfountain, published on GitHub under the GPL-3.0 license. It is a 4-layer board measuring 67.1 × 22.5 mm, with 16 components from 13 distinct parts.
By type, the board carries 6 diodes, 4 capacitors, 2 connectors and 1 resistor.
It belongs with the test & measurement designs in this gallery.
From the project
A lower RAM module for the ZX Spectrum
This is a hardware module which implements the lower 16K RAM bank for a 16K or 48K ZX Spectrum microcomputer.
The memory bank is normally implemented with 8 4116 DRAM ICs. These ICs are no longer in production, and although not yet hard to get hold of, the ones which are available are 50 years old and have inevitable frailties. This project implements the required 16K of memory using a modern SRAM IC.
Zx spectrum lower ram bill of materials (BOM)
16 components, 13 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 2 | Conn_01x08_Male | PinHeader_1x08_P2.54mm_Vertical | J1, J8 |
| 1 | 74HCT04 | SOIC-14_3.9x8.7mm_P1.27mm | INV1 |
| 1 | 74HCT574 | SO-20_5.3x12.6mm_P1.27mm | LATCH1 |
| 1 | IS62C256AL-45ULI | SOIC127P1210X305-28N | SRAM1 |
| 1 | D1 | PinHeader_1x01_P2.00mm_Vertical | D1 |
| 1 | D2 | PinHeader_1x01_P2.00mm_Vertical | D2 |
| 1 | D3 | PinHeader_1x01_P2.00mm_Vertical | D3 |
| 1 | D4 | PinHeader_1x01_P2.00mm_Vertical | D4 |
| 1 | D5 | PinHeader_1x01_P2.00mm_Vertical | D5 |
| 1 | D6 | PinHeader_1x01_P2.00mm_Vertical | D6 |
| 3 | C_Small | C_1206_3216Metric | C1, C2, C3 |
| 1 | C_Small | C_Disc_D4.3mm_W1.9mm_P5.00mm | C4 |
| 1 | 270R | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1 |
Zx spectrum lower ram design files
The KiCad project lives in the derekfountain/zx-spectrum-lower-ram repository on GitHub; these links point at the commit this page was built from.
- Layoutslrm/slrm.kicad_pcb
- Schematicslrm/slrm.kicad_sch
Zx spectrum lower ram: common questions
How big is the Zx spectrum lower ram PCB?
The Zx spectrum lower ram measures 67.1 × 22.5 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the Zx spectrum lower ram?
16 components, from 13 distinct parts. The full bill of materials is listed on this page.
Where can I download the Zx spectrum lower ram design files?
From the derekfountain/zx-spectrum-lower-ram repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Zx spectrum lower ram design in my own project?
Yes, under the terms of its GPL-3.0 license, which derekfountain chose for the repository.
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