shibosoftwaredev/f1c100s-linux-nema17-stepper-controller

motor-harness.md

# Motor harness — do not assume the connectors match

The PCB uses a four-pin **JST-PH, 2.00 mm** header. The current
[StepperOnline 17HS13-0404S1 listing](https://www.omc-stepperonline.com/nema-17-bipolar-1-8deg-26ncm-36-8oz-in-0-4a-12v-42x42x34mm-4-wires-17hs13-0404s1)
describes a 1 m cable with a **2.54 mm** connector. Pitch alone does not identify
that motor-side connector family, keying or phase order. It is not directly
compatible with the board header. The CAD cable is a routing illustration, not
proof of an off-the-shelf plug-to-plug harness.

## No hand-crimping option

[Adafruit 5088](https://www.adafruit.com/product/5088) is an off-the-shelf four-pin
PH-compatible cable pair with 2.00 mm pitch, stranded 26 AWG wire and about
20 cm per half. Use the half with the housing that mates to the PCB's male PH
header. This needs **four soldered, individually heat-shrunk splices** to the
motor leads; it is not a solder-free or plug-and-play conversion. Do not splice
or unplug a motor with the board powered.

1. Identify the two winding pairs with an ohmmeter; each winding is nominally
   30 Ω. Do not trust a pigtail's wire colours to identify phases.
2. Map the pigtail housing's physical pins by continuity, following the PCB's
   pin-1 marking: 1 B+ (motor red), 2 B− (blue), 3 A− (green), 4 A+ (black).
   Verify actual motor colours against its supplied drawing.
3. Solder, insulate each joint separately and add strain relief clear of the
   shaft, screw heads and hot driver. Leave a relaxed bend between the motor
   outlet and board connector; do not tension the small connector.
4. Verify phase resistance and absence of phase-to-case shorts at the finished
   plug. On this software-current revision, keep `R_ISET_210` DNP; request
   200 mA while disarmed and verify `--limit` is ready before the first unloaded
   move. Use the matched new PCB/MCU firmware; this is a nominal peak setting,
   not a calibrated phase-current measurement.

For a completely solder-free adapter, first obtain the exact supplied motor
plug/housing specification and confirm its pin order. Do not buy an unspecified
“2.54 mm to JST” cable based only on pitch. Connector changes on the PCB would
require a separate footprint, clearance and routing review.