I2C Max Frequency

[eiadj]

Regarding I2C, the Nordic specifies a typical value for frequency in different modes (nrf52832/40); however there is no tolerance specified for the frequency. What is the deviation in frequency that is acceptable? We currently have it set to 400kHz but are seeing higher frequencies (410kHz-420kHz) and want to ensure this won't cause issues.

Also, we are using 10K pull-ups on the I2C lines, is this acceptable?

Thanks!

[haakonsh]

See [219] TWIM: I2C timing spec is violated at 400 kHz, Also the frequency at the 400kHz setting is actually 410-420kHz. You can try to lower this registers value until you get the desired frequency.

Also, we are using 10K pull-ups on the I2C lines, is this acceptable?

 The nRF52 has internal pull-ups of 13k (+/- 3k), so you might as well use those. A few TWI set-ups require external 4.7k pull-ups though, it depends on what you're trying to drive. 

[eiadj]

Thanks! I will check and see if this errata is addressed and make the pull-up modifications. Will update once we get those results.