Testpinout

Testpinout refers to the specification and diagram that describe how the pins of a test connector or header map to the signals, voltages, and supplies used during testing and programming of electronic devices. It serves as a reference for manufacturing test, debugging, service, and field updates, enabling test equipment to connect to a device under test (DUT) correctly and safely.

Pinouts identify pin numbers, signal names, electrical characteristics, and any reserved or no-connect pins. They are essential for bed-of-nails or pogo-pin fixtures, in-circuit testers, and interfaces used for programming or debugging, such as JTAG, SWD, SPI, UART, I2C, or simple GPIO headers. Common form factors include 2x5 or 2x10 headers for JTAG, as well as 4-, 6-, or 8-pin serial debug headers and IDC-style connectors. Pinout diagrams may accompany boards as silk-screen notes, in design files, or in service manuals.

Documentation and maintenance are important, since pinouts can change between revisions. Updated diagrams help ensure correct cable or harness compatibility and reduce test errors. In practice, a well-defined testpinout supports automated test equipment (ATE) and programming fixtures, improves repeatability, and aids troubleshooting by clarifying signal mappings and voltage expectations.

Practical considerations include verifying voltage levels and polarity, avoiding conflicts with functional signals, providing isolation or current limiting where appropriate, and applying proper ESD protection. Clear labeling and versioned documentation help ensure that test pinouts remain accurate across product lifecycles.

See also: pinout, JTAG, boundary scan, ICT, ATE, pogo pin.