Serial port comunication on PC

massimofaugno wrote on Thursday, March 05, 2009:

I’m trying to use freeRTOS on an old PC with DOS installed.
I am created two tasks:

  xTaskCreate( vPLC_Task, "PLC", mainPLC_STACK_SIZE, NULL, tskIDLE_PRIORITY + 10, NULL );
  xTaskCreate( vHMI_Task, "HMI", mainHMI_STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
Can I use in "PLC" task the functions "_bios_serialcom" of
"Watcom C" without necessarily creating a driver for the serial port?
Do I need some precaution?
Can I have problems?

Thanks to all

sotd wrote on Thursday, March 05, 2009:

Dont no directly but some openwatcom bios calls leave interrupts enabled so a critical section is not always a possibility.

massimofaugno wrote on Friday, March 06, 2009:

Thanks sotd,
Have you any suggestions to create a little slave application that use
serial port without write driver?
This routine that runs in "PLC" task send data to a master when requested.