BOM: the second module is a WT61 plus (TTL); the WT61 datasheet may not apply to it
/ crosscheck (push) Successful in 0s

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz
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2026-10-14 00:19:22 +09:00
parent 43a2b8bf0b
commit 645bad819e
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@@ -166,7 +166,10 @@ Header facts (carrier board spec SP-11324-001 v1.3, Table 3-3 and 5-3; raw copy
"TTL level", so if it is ever fed 5 V, first check that its idle TX reads ~3.3 V. "TTL level", so if it is ever fed 5 V, first check that its idle TX reads ~3.3 V.
- Power comes from the header's 3.3 V supply pin (1 or 17), a regulated rail on the carrier board. Not from a GPIO: a GPIO pin is a signal - Power comes from the header's 3.3 V supply pin (1 or 17), a regulated rail on the carrier board. Not from a GPIO: a GPIO pin is a signal
and is not meant to power anything. and is not meant to power anything.
- **The second module (2026-10-14) speaks WitMotion's newer register protocol, not the 3-byte commands** in smart-serow's `IMU.md`: - **The second module (2026-10-14) is a different product: "WitMotion WT61 plus, TTL version"**, in different packaging. The WT61
datasheet v24-0429 (the KB's) describes the plain WT61 and may not apply to it; rates, defaults and commands below are what this module
did, not what that datasheet says. Its own manual is still to find.
- **It speaks WitMotion's newer register protocol, not the 3-byte commands** in smart-serow's `IMU.md`:
it ignored `FF AA 63`. It came at 9600 baud / 10 Hz (a rate the datasheet does not list). Commands are 5 bytes, it ignored `FF AA 63`. It came at 9600 baud / 10 Hz (a rate the datasheet does not list). Commands are 5 bytes,
`FF AA <register> <low> <high>`, each run as **unlock `FF AA 69 88 B5`, the write, save `FF AA 00 00 00`**, all at the module's `FF AA <register> <low> <high>`, each run as **unlock `FF AA 69 88 B5`, the write, save `FF AA 00 00 00`**, all at the module's
current baud. Done on the car Orin, checking after each step: current baud. Done on the car Orin, checking after each step: