3MHz is the max SCK I use. A lot of that time is spent switching modes between three types of SPI devices with auto-CS. If you do multi-byte SPI transactions to one device, the SPI transfer speed is pretty good but there is a lot of dead-time inside the MCP2210. So if a SPI device has a FIFO/Stream mode for burst data, use it.Nice! An interval of 14ms for each transaction is acceptable, but I'm guessing that the MCP2210 is a tad slow. The CP2130 was better in that respect. That slowness might be problematic in my use case, if I am going to use it to replace the CP2130 in one of my USB test switches. I will need to take five measurements from an LTC2312CTS8-12 ADC, and the total of all those transactions, plus reading 5 GPIOs, must be well within an interval of 50ms!
By the way, what bitrate are you using?
Test setup, need to clean the scope screen.
24 byte SPI transfer from IMU, 1.3ms
Byte inter-gap spacing, 66us
Per byte timing, ~3us per byte