UART issue DSPIC33EP

[MinhNguyen]

Hi,
I am having very weird issue with communication between software application and a DSPIC33EP through UART channel.
The software application i constantly sending down the command string to the MCU and the MCU will return the command as received for confirmation purpose. The command string is varied between 5-9 characters.
If I use a hyper-terminal to test the communication between computer and MCU, all the command will be detected, return and executed correctly without any issue.
But when the software application is running, once in a while there are characters are unable to detected. I am using the serial port monitor software to check the commands go in and out the serial port, I was able to see a correct command get send and the return is missing some character.
i am using CCS compiler version 5.09 PCD, 70MHz internal clock, with RS232 set up as #use rs232(UART1, baud=38400, stream=UART_PORT1)
Has anyone come across this issue and how did you start to troubleshoot this issue?
Thank you very much for your help.
Minh

 

[KlausST]

Hi,

UART problem are discussed very often here.

In 90% (I assume) there is a baudrate mismatch. (Check if you are within specified tolerances)

In your case I assume you don´t have interrupt driven UART communication on DSPIC side. Or your DSPIC_UART input buffer is too small.
Maybe the processing of the received data (processing in main loop, data from UART_buffer) fails, or the missing of atomic UART_buffer handling generates problems.


These are just assumptions .... you surely know that you didn´t send any hardware information and you sent no code ... so how can we know?

Klaus