Section 12.3 of the ICM-42688-P datasheet states "Upon bootup the device comes up in SPI mode." -- the section goes on to describe register settings to set other modes modes (i2C and i3C)
But how does one perform the initial programming? I'm testing a board that has the 42688-P wired for I2C per the datasheet. And I can connect to other I2C devices on the bus. But the 42688-P is not responding.
The datasheet could be clearer on how/why the chip transitions from SPI mode at boot to another mode -- I suppose I could bit-bang the settings as an SPI interaction, but is there something I am missing in the existing documentation?
Thanks,
Just to elaborate: Section 12.3 goes on to describe register settings specific to I2C, I3C, and SPI modes. But how does one get the appropriate settings established if the chip boots in SPI mode, but its wired for I2C? Does the chip somehow detect the I2C-based SDA/SCL START interaction and switch modes automatically? If so, that's not clear from the documentation I came across. Again, wondering what I might have missed.
Hi,
You can check out our driver to have a better understanding of the I2C setup.
It is located here: https://invensense.tdk.com/developers/software-downloads/#smartmotion
Download the file named: DK-42688-P SmartMotion eMD 2.0.9 (Updated 2023.04.03)
Thanks. I did do that. After examining all that, it certainly looks like a 42688 wired for I2C will respond to I2C-based commands by following the "init" programming sequence - all without other special considerations.
Hi,
how should I use eMD? Do we have a user guide for eMD?
Hi,
You will see a file named "doc" under the eMD package when you download it. There is a user guide in that file. In order to run any eMD example firmware provided in the eMD package, you need Microchip Studio (https://onlinedocs.microchip.com/pr/GUID-ECD8A826-B1DA-44FC-BE0B-5A53418A47BD-en-US-12/index.html?GUID-8F63ECC8-08B9-4CCD-85EF-88D30AC06499)