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6 layers114 × 48 mmCache6400, the printed circuit board in 3D

Modern reverse-engineered drop-in L2 cache card for Power Macintosh 6400/6500 — replaces the unobtanium IDT7MP6071 with an ATF1508AS CPLD + IS61C1024AL SRAMs

Size
114 × 48 mm
Copper layers
6
Thickness
1.6 mm
Parts
26
Nets
186
Pads
598
Tracks, vias
0, 0
Pours
2
Routed
Not yet
KiCad
KiCad 7 (file 20221018)
Created
2 May 2026
Updated
2 May 2026

Overview

Cache6400 is an open-source printed circuit board by Kelsidavis, from the Kelsidavis/cache-goblin repository on GitHub. It is a 6-layer board of 114 × 48 mm with 26 parts on 186 nets.

Its parts include 10 ICs, 6 resistors, 4 capacitors, 4 diodes and 2 connectors.

README

kicad/README.md

KiCad project — cache6400

Open cache6400.kicad_pro in KiCad 7 (or 8 — it will offer to upgrade).

Layout

  • cache6400.kicad_pro — project file

  • symbols/cache6400.kicad_sym — custom symbol library (SRAM today; CPLD added once we lock pinning)

  • symbols/cache_slot.kicad_sym — auto-generated by scripts/build_slot_symbol.py from docs/pinout.csv

  • scripts/build_slot_symbol.py — symbol generator. Re-run any time the pinout CSV changes:

    sh
    python3 kicad/scripts/build_slot_symbol.py

What's blocked on hardware

Schematic and PCB layout cannot start until docs/pinout.csv is filled in. See docs/probe-protocol.md for the procedure.

Library tables

To make the custom symbols visible in this project, add to sym-lib-table (KiCad will create it on first open):

text
(lib (name "cache6400")(type "KiCad")(uri "${KIPRJMOD}/symbols/cache6400.kicad_sym")(options "")(descr ""))
(lib (name "cache_slot")(type "KiCad")(uri "${KIPRJMOD}/symbols/cache_slot.kicad_sym")(options "")(descr ""))

Parts

26
QtyValueFootprintReferences
8SOJ-32cache6400:SOJ-32_10.16x20.32mm_P1.27mmU2, U3, U4, U5, U6, U7, U8, U9
6R_0603_1608MetricResistor_SMD:R_0603_1608MetricR1, R2, R3, R4, R5, R6
4LED_0805_2012MetricLED_SMD:LED_0805_2012MetricD1, D2, D3, D4
2C_0603_1608MetricCapacitor_SMD:C_0603_1608MetricC3, C4
2C_0805_2012MetricCapacitor_SMD:C_0805_2012MetricC1, C2
1CACHE_SLOT_PM6400cache6400:CACHE_SLOT_PM6400J1
1PinHeader_2x05_P1.27mm_VerticalConnector_PinHeader_1.27mm:PinHeader_2x05_P1.27mm_VerticalJ2
1TQFP-100_14x14mm_P0.5mmPackage_QFP:TQFP-100_14x14mm_P0.5mmU1
1TSOP-II-44_10.16x18.41mm_P0.8mmPackage_SO:TSOP-II-44_10.16x18.41mm_P0.8mmU10

Questions

How big is the Cache6400 PCB?

It measures 114 × 48 mm and has 6 copper layers, 1.6 mm thick.

What parts does the Cache6400 use?

26 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Cache6400 KiCad files?

From the Kelsidavis/cache-goblin repository on GitHub, at the commit this page was made from: the board is kicad-quilter/cache6400.kicad_pcb and its schematic kicad-quilter/cache6400.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Cache6400 design in my own project?

Its repository states no licence, so its author keeps all rights: ask Kelsidavis before reusing the design.

More from Kelsidavis/cache-goblin

1
  • 4 layers114 × 48 mmCache6400, the printed circuit board in 3D

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    Kelsidavis/cache-goblin

    Modern reverse-engineered drop-in L2 cache card for Power Macintosh 6400/6500 — replaces the unobtanium IDT7MP6071 with an ATF1508AS CPLD + IS61C1024AL SRAMs

    18 parts

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