AM3352: Probability of parity bit error

After testing, it has been found that the serial port of the AM335x chip has a higher probability of encountering parity errors. In the manual, a baud rate of 115200 is recommended. By capturing data with a logic analyzer for statistical analysis, it was observed that the probability of parity errors is 0.00083%. In the same test environment, the ST chip did not encounter any parity errors. In order to eliminate the interference from peripheral circuits, I directly connected the TX and GND of the chip's IO port to the logic analyzer. The test results were consistent with the previous findings, indicating that it is not related to the peripheral circuits. 
Since most high baud rate configurations are not within the range specified in the manual, there is a significant discrepancy between the actual baud rate and the configured one. However, by directly analyzing the data using a logic analyzer, the actual baud rate can be determined for decoding. In the tests, it was found that configuring odd or even parity had no impact on the experimental results, so a configuration of 8 data bits, 1 stop bit, and even parity was used. The test data is as follows:

The figure below shows occasional parity bit errors that occurred at a baud rate of 115200.

Configuration details: The serial port configuration clock adopts the default 48M as specified in the manual.
I hope to receive a practical solution to this issue.

Gary Lu：

Hello，

To address this problem, you can try the following practical solutions:

1. Adjust the baud rate: Since the actual baud rate may differ from the configured one, you can experiment with slightly higher or lower baud rates to see if it reduces the occurrence of parity errors. You can use a logic analyzer to analyze the data and determine the actual baud rate for decoding.

2. Consider using a lower baud rate: If adjusting the baud rate does not provide satisfactory results, you can try lowering the baud rate to see if it helps in reducing parity errors. This might be a viable solution if the lower baud rate still meets your communication requirements.

3. Check hardware connections: Ensure that all hardware connections are secure and properly grounded. Intermittent or loose connections can lead to signal integrity issues and potentially cause parity errors. Double-check the wiring between the chip's IO port and the logic analyzer.

4. Review power supply stability: Instability in the power supply can contribute to signal integrity issues. Verify that the power supply to the AM335x chip is stable and meets the required specifications.

Regards，

Gary