Connectors

This is the technician reference for the Attaky connector standard: the three connector types and the complete pinout of every position. For the high-level picture of how modules join, start with the Overview; for which combinations are valid, see the Compatibility Matrix.

The three connectors

These are standard connector types — a board-to-board (BTB) on the back, a 12-pin flat-flex (FPC), and a 7-pin SH1.0 power connector — and the docs refer to them this way throughout. The per-position tables below give exactly what each one carries.

Position numbering

Every position has a host-side label and a module-side label. The prefixes differ on purpose so the two are never confused: the host (Core) side uses F-BTB / C-FPC / C-PIN, and the module side uses M-BTB / M-FPC / M-PIN.

Host-side and module-side numbers are not 1:1 — the connectors mate with a fixed crossover, so a given host position lands on a different module position. For the 50-pin BTB the mapping is F-BTB(n) ↔ M-BTB(76 − n) for positions 26–50 and F-BTB(n) ↔ M-BTB(26 − n) for positions 1–25 (so F-BTB29 ↔ M-BTB47, F-BTB50 ↔ M-BTB26). Every table below is the host-side view. Each module's own datasheet gives its module-side numbering.

Board-to-board (BTB) — 50-pin

The back connector. Of its 50 positions, 34 are signal — 22 straight from the MCU and 12 from the Core's two on-board GPIO expanders — and the other 16 are supply rails, ground, and a few unused positions.

Power and ground

Signal pins

Flat-flex (FPC) — 12-pin

The Core exposes three FPC taps — left, right, and bottom — all the same 12-line bus, so a Control module attaches to whichever is convenient. Control modules pass the bus straight through (an UP and a DOWN connector), so one chains below another — a keyboard and a gamepad can be used together this way.

The two interrupt lines (C-FPC5, C-FPC6) are shared — a keyboard and a gamepad drive the same pair — so when one fires, the firmware scans both devices to see which it was. That's what lets a keyboard and a gamepad be used together on the same bus; each still has its own I²C address.

Power (SH1.0) — 7-pin

A cable channel for the Power module, on the bottom of the Core. It carries the supply rails, the shared I²C bus (so the battery gauge stays on the main bus), and the gauge's alert line. Because it's a separate connector from the BTB, a Power module can attach here while an Expand sits on the back.

On Power: Standard Cell 1.0, the 7-pin connector and the back BTB are alternative routes, never simultaneous — the gauge alert line (C-PIN7 and F-BTB7) is the same net, so only one form is used in a given build. Check another Power module's datasheet for its supported routes.

On the module side

Each module uses the connector channel for its category, but passthrough is not a feature of every module:

• Expand module — its M-BTB mates with the Core's back F-BTB, or with a compatible Power module's rear passthrough. Current Expand modules end the stack; they do not provide a rear connector for another Expand.
• Power module — the supported connection route is listed on that module's datasheet. A Power module may use a front M-BTB, a 7-pin M-PIN, or both as alternatives. It can sit between the Core and an Expand only when its datasheet explicitly lists a rear F-BTB passthrough. Power: Standard Cell 1.0 provides this passthrough; it connects by BTB or by the 7-pin cable, never both at once.
• Bottom Control module — the current Keyboard and Gamepad each use an UP M-FPC and a DOWN M-FPC passthrough. That lets the two bottom Control modules share the bus and chain below the Core.

See also

• I²C Address Map — every address on each bus
• Frame — how the connectors are used to assemble a build
• Swap a Module — handling connectors safely
• Compatibility Matrix — which modules can share the bus