Serial Communication problem: application hangs when we write command every 250ms

when we try to write data into serialport in a timegap of 250ms the application hangs frequently. How should we achieve serial data transfer in this scenario?

@centurymetering, please tell us which computer module you are using, which operating system and BSP version. How is the hardware setup look like? Thanks.

Our technical details are as follows.
SOM : colibri T20 module , 512 MB NAND FLASH
Carrier board : Iris Carrier board.
Operating system : Windows Embedded Compact 7
IDE : Visual studio - 2008
Language : C#
Project type :Smart device projects
Templates : Device application (Because we have 7 inch RGB LCD Connected to it.).

Connection details :

UART C TTL output of Iris board is connected to TTL to 485 convertor. In 485 bus two more devices are connected . Communication protocol is MODBUS - RTU. The application is to send command from the master i.e Toradex SBC to the other two slaves and process the response. But In this application time is of major concern . So we want to communicate with the as fast as possible. Our next step will be increasing the BAUD RATE , but with basic 9600 baud rate itself the communication hangs after few transmissions and receptions.

We have used Event handler for collecting the received data. Kindly let us know if any solutions available.

Thanks & Regard,
Century

We fixed a freeze issue related to UART in WinCE BSP V2.0beta4 for T20 and T30 modules. You can find this in our software release notes:
http://developer.toradex.com/software/windows-embedded-compact/t20-t30-wec-software/release-details?view=release-notes&issue=21989
I’m not sure if your problem is related, but please give it a try and let us know if V2.4beta1 solves the issue. Thanks.