I'd like to know please, what is the maximum I2C speed that can be used with the ADAU1701? I'd like to use 400Khz or even 1Mhz, but I noticed that USBi communicates at 100Khz, so I'm a little concerned about higher speeds.
The ADAU1701 is characterized to operate at the 400-kHz Fast-mode (Fm) defined in Version 1.0 (the first standardized version of the I2C protocol).
Followup - what is the minimum speed for reliable I2C communication? Are speeds such as 100kHz supported, or only 400kHz?
100Khz is supported. By the way, 100Khz is the frequency that USBi operates originally. I've used both 100 and 400Khz, they work just fine.
We haven't actually characterized the minimum speed. I'm not sure if there actually is a "time-out" or anything, so you can probably operate the I2C bus at very low speeds. We have tested down in the tens of kHz with no problems.
Interesting! Because I found that USBi actually operates at 80Khz, but I though it was a glitch or something like that because it's not a commonly used frequency.
We use the built-in I2C functionality in the Cypress USB microcontroller... nothing fancy. We just call their pre-made I2C write functions and the chip does the rest. So, we're really at the mercy of the clock rate they chose for that particular IC design.
Retrieving data ...