canbus: note pigtail wiring colors (green=CAN-L, blue=CAN-H)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
wes
2026-06-12 11:42:21 -04:00
co-authored by Claude Opus 4.8
parent cda537da29
commit 81bd58206d
2 changed files with 2 additions and 0 deletions
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@@ -36,6 +36,7 @@ state + what's left.
(the one with the terminator), per `README.md` → "Physical connection". (the one with the terminator), per `README.md` → "Physical connection".
⚠️ Meter the port first: data idles ~2.5 V, power reads ~12 V; 12 V on CAN-H/L ⚠️ Meter the port first: data idles ~2.5 V, power reads ~12 V; 12 V on CAN-H/L
destroys the transceiver. destroys the transceiver.
- **Pigtail wiring (as crimped):** green = CAN-L, blue = CAN-H.
- **GPIO:** transceiver `CTX/D` ← ESP32 `GPIO5` (tx_pin), `CRX/R``GPIO4` - **GPIO:** transceiver `CTX/D` ← ESP32 `GPIO5` (tx_pin), `CRX/R``GPIO4`
(rx_pin). Adjust `substitutions:` in the YAML if you wire differently. (rx_pin). Adjust `substitutions:` in the YAML if you wire differently.
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@@ -240,6 +240,7 @@ re-light.
4. Land the two wires on the transceiver's CAN-H / CAN-L. The transceiver's 4. Land the two wires on the transceiver's CAN-H / CAN-L. The transceiver's
onboard 120 Ω re-terminates that end (keeps exactly 2 terminators: controller onboard 120 Ω re-terminates that end (keeps exactly 2 terminators: controller
+ your node). **Never** add a terminated node in the *middle* of the bus. + your node). **Never** add a terminated node in the *middle* of the bus.
- **This rig's pigtail (as crimped):** **green = CAN-L, blue = CAN-H.**
5. Revert = unplug, re-seat the terminator. 5. Revert = unplug, re-seat the terminator.
CAN-H vs CAN-L: harmless if swapped — the bus just goes silent; flip the two CAN-H vs CAN-L: harmless if swapped — the bus just goes silent; flip the two