NRF5 I2C standard speed 250kHz

[thomafred]

The NRF5 I2C-driver SCL-line measures 250kHz when configured with standard speed (I2C_SPEED_STANDARD), while fast speed (I2C_SPEED_FAST) measures 100kHz.

The i2c-bus specifiation lists the following bidirectional speeds (section 5 of this document)

• Standard-mode (Sm) - bit rates up to 100 kbit/s
• Fast-mode (Fm) - bit rates up to 400 kbit/s
• Fast-mode Plus (Fm+) - bit rate up to 1 Mbit/s
• High-speed mode (Hs-mode) - bit rate up to 3.4 Mbit/s

[anangl]

250 kHz is the default frequency set in the TWI peripheral after reset. It looks like the configuration register is not changed at all. Are you sure that the i2c_configure function is successful (i.e. it returns 0)?
Perhaps you don't use the macro I2C_SPEED_SET when configuring the speed?
When I do:

int result = i2c_configure(i2c_dev, I2C_SPEED_SET(I2C_SPEED_STANDARD));

the speed is configured correctly.

[carlescufi]

Not a bug.