Hello,
Customer designed his own am3352 board. It communicated to modbus via QT. UART1 is for debug purpose and UART2 is for modus communication.
Problem:
After running for a while, the UART baud rate is increasing, please see below timing wave (115200bps). The white wave is normal, the yellow wave is drifting.
1. uart2 baud rate is increasing too after uart1.
2. The baud rate increased about 20%.
3. The issue occurs randomly. Sometimes it occurred in 1~2 hour and sometimes it occurred after 3~5 days.
4. 30 pieces of boards run for 24 hours, about15 pieces boards have the problem. UART can't work but other peripherals like Touchscreen, usb, keys are normal.
5. . linux version is 3.2.0. qt 4.8.7. linux 4.19.59 has the same problem.
6. Decreasing UART2 to 9600bps has the same problem.
7. Changing crystal has the same problem.
Thanks.
Rgds
Shine
