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Tkmem128-ii

lrrosa·tkmem128-ii·hardware/tkmem128-ii.kicad_pcb

Tkmem128-ii PCB layout, top view — open source board by lrrosa
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About the Tkmem128-ii PCB

Tkmem128-ii is an open source PCB design by lrrosa, published on GitHub under the CERN-OHL-S-2.0 license. It is a 4-layer board measuring 78.7 × 66 mm, with 19 components from 14 distinct parts.

Other key parts include the GAL20V8B, 74HCT273, AS6C1008-55PCN and 27C256. By type, the board carries 6 capacitors, 4 ICs, 4 resistors, 3 jumpers, 1 connector and 1 diode.

It belongs with the test & measurement and retro computing designs in this gallery.

From the project

TKMEM-128 II — expansão de 128K/512K paginados (padrão ZX Spectrum 128) para TK90X, TK95 e ZX Spectrum 48K, redesenhada em KiCad. Derivada do projeto do Velesoft (2009) e da TKMEM-128 da Luccas Eletrônica (2012). CERN-OHL-S v2.

Expansão externa de 128 KB (ou 512 KB) de RAM paginada no padrão ZX Spectrum 128 para TK90X, TK95 e ZX Spectrum 48K. Redesenho completo em KiCad 10, com arquivos de fabricação prontos.

Ele não inventa o circuito: junta e redesenha dois trabalhos anteriores.

Créditos também a Flávio Matsumoto, que sugeriu o circuito do Velesoft para os TKs e identificou a caixa Patola PB 085/3, e a Daniel Jose Viana (danjovic), cujo trabalho documentou as cotas da placa para essa caixa.

Tkmem128-ii, from the project README
From the project README

Main components on the Tkmem128-ii

GAL20V8B74HCT273AS6C1008-55PCN27C256

Tkmem128-ii bill of materials (BOM)

19 components, 14 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
GAL20V8B
U1
1
74HCT273
U2
1
AS6C1008-55PCN
U3
1
27C256
U4
1
Barramento TK
J1
1
SELECIONA ROM
JP1
1
ROMCS BARRAMENTO
JP2
1
ZX128/ZX512
JP3
1
LED
D1
5
100N
100n
C1, C2, C3, C4, C5
1
10U
10u
C6
2
1k
R2, R4
1
2K2
2k2
R3
1
0R
R5

Tkmem128-ii design files

The KiCad project lives in the lrrosa/tkmem128-ii repository on GitHub; these links point at the commit this page was built from.

Tkmem128-ii: common questions

How big is the Tkmem128-ii PCB?

The Tkmem128-ii measures 78.7 × 66 mm, has 4 copper layers and is 1.6 mm thick.

How many components are on the Tkmem128-ii?

19 components, from 14 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Tkmem128-ii design files?

From the lrrosa/tkmem128-ii repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Tkmem128-ii design in my own project?

Yes, under the terms of its CERN-OHL-S-2.0 license, which lrrosa chose for the repository.

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