Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
Supported Systems / Found On — Retro Machine Hubs
This connector is used on the following retro computer systems. Click any colour-coded badge below to open its full board-level repair, diagnostic, and schematic Machine Hub:
Connector Specifications
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| 1 | +5V DC (VCC) | Pwr | +5.0 V DC Regulated Supply (powers 74HC157 & Multitap) | Red (+5V) |
| 2 | D0 (UP / BUTTON I) | In | Data Bit 0: UP (when SEL=HIGH) or BUTTON I (when SEL=LOW) | White |
| 3 | D1 (RIGHT / BUTTON II) | In | Data Bit 1: RIGHT (when SEL=HIGH) or BUTTON II (when SEL=LOW) | Blue |
| 4 | D2 (DOWN / SELECT) | In | Data Bit 2: DOWN (when SEL=HIGH) or SELECT (when SEL=LOW) | Green |
| 5 | D3 (LEFT / RUN) | In | Data Bit 3: LEFT (when SEL=HIGH) or RUN (when SEL=LOW) | Yellow |
| 6 | DATA SEL (SEL Strobe) | Out | Multiplexer Select Output from HuC6280 K-Port Bit 0 (1=D-Pad, 0=Buttons) | Orange |
| 7 | /ENABLE (/CLR Strobe) | Out | 74HC157 Strobe / Multitap Counter Reset from HuC6280 K-Port Bit 1 (0=Enabled) | Brown |
| 8 | GND (0 V Ground) | GND | 0 V Common Ground & Shield Return (Pin 8 + Outer Shell) | Black (GND) |
How the PC Engine 5-Player Multitap & HuC6280 I/O Port Work
Inside every NEC TurboPad (PI-PD001 / PI-PD002) is a single 74HC157 quad 2-to-1 data selector IC. Rather than shifting 8 bits one at a time like the NES, the PC Engine's HuC6280 CPU I/O port (`$1000`) uses two control outputs — Pin 7 (`SEL` Data Select) and Pin 8 (`/CLR` Clear / Enable) — to read all 8 buttons in two 4-bit nibbles across Pins 2, 3, 4, and 5 (`D0–D3`): when `SEL` is HIGH (+5V), `D0–D3` report Up, Right, Down, Left; when `SEL` is LOW (0V), `D0–D3` report Button I, Button II, Select, and Run!
- Why the PC Engine Only Has One Controller Port on the Console: Because Pin 7 (/CLR) resets a 5-stage counter inside the official NEC PI-PD003 Multitap while transitions on Pin 6 (SEL) advance to the next player port after each 2-nibble read, a single 8-pin port natively supports up to 5 players!
- Dead Directions or Stuck Buttons: If Up/Right/Down/Left work fine but Buttons I, II, Select, and Run do nothing (or vice versa), the `SEL` wire (Pin 6) in the controller cord has broken or the 74HC157 inside the pad has failed. If NO controller works on the console, inspect the EMI filter array (`EMI1–EMI6`) right behind the controller socket on the PC Engine PCB.