I2C speed outside the specifications of various IMUs #117

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MrUnknownDE · 2026-04-05T17:51:53+02:00

MrUnknownDE commented

2026-04-05 17:51:53 +02:00

Originally created by @unlogisch04 on 3/17/2025

cade3ebcf5/src/debug.h (L85)

I believe we should not set the default i2c speed higher than a normal sensor can handle.
It does not affect ESP8266 as on default frequency (80MHz) it is limited to 400kHz.
But it affects all ESP32-C3 variants

If we rely need higher i2c clock speeds it would make some stuff more complicated.
As it affects different parts:

how long extension-cables works
compatibility with IMU's
possible combination of IMU's / magnetometer

If there is rly need to change it, we should do it either in defines.h / webflasher, or per production board.
But i think this is something that has do be discussed.

per datasheet this sensors do not support more than 400kHz:

MPU6050
MPU6500
MPU9250
BNO080
BNO085
BNO086
ICM20948
LSM6DS3TRC
LSM6DSO

edit added list of IMU

*Originally created by @unlogisch04 on 3/17/2025* https://github.com/SlimeVR/SlimeVR-Tracker-ESP/blame/cade3ebcf597bcab9ad693b81925a9eb2d973d79/src/debug.h#L85 I believe we should not set the default i2c speed higher than a normal sensor can handle. It does not affect ESP8266 as on default frequency (80MHz) it is limited to 400kHz. But it affects all ESP32-C3 variants If we rely need higher i2c clock speeds it would make some stuff more complicated. As it affects different parts: - how long extension-cables works - compatibility with IMU's - possible combination of IMU's / magnetometer If there is rly need to change it, we should do it either in defines.h / webflasher, or per production board. But i think this is something that has do be discussed. per datasheet this sensors do not support more than 400kHz: - MPU6050 - MPU6500 - MPU9250 - BNO080 - BNO085 - BNO086 - ICM20948 - LSM6DS3TRC - LSM6DSO edit added list of IMU

MrUnknownDE closed this issue

2026-04-05 17:51:53 +02:00

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Reference: github/SlimeVR-Tracker-ESP#117