Problem with UpXtreme i7 Uart on Hat40 at 3000000 baud, but works on Up and Up2

buddye

This is on Ubuntu 20.04.

I'm using an IMU chip with async serial support, but only at 3000000 (3 million!) baud. It sends short packets with long delays in between, but data really is 3000000 baud. The packets arrive at 20Hz.

I connect this device to the HAT40 serial uart, wrote a C++ program to read and display the packets. My program runs fine on an Up board and Up2 board, but hangs after a short while on an Up Xtreme i7.

I have tried setserial on the serial port with low_latency, but no help.

So: same hardware device, same software, same ubuntu linux, works on Up and Up2, but not Up Xtreme i7.

Any help on what this could be? How can I tell what chip implements the uart and see if I have latest driver?

thanks,
buddy e