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Syntax Description
ASSIGN Display serial channel I/O assignments.
ASSIGN channel < inreg > outreg Change serial channel I/O assignments.

The ASSIGN command lets you display and change the input and output sources for the specified serial channel.

The following table shows the supported channels and their default input register (inreg) and output register (outreg) settings.

Channel Default Inreg Default Outreg Description
COM1 None None COM port 1 on the PC.
COM2 None None COM port 2 on the PC.
COM3 None None COM port 3 on the PC.
COM4 None None COM port 4 on the PC.
WIN SIN or S1IN SOUT or S1OUT The Serial window.

Currently, µVision3 for windows supports the following channels: WIN, COM1, COM2, COM3, and COM4. The WIN channel is the Serial window. The COMx channels represent the serial communication ports of the PC which you may use to communicate with the simulated CPU and your target program. You must set the parameters for the PC serial ports using the MODE command.

The names of the input register and output register are defined by the CPU you have selected from the device database. The available VTREGs can be listed with the command DIR VTREG.

>ASSIGN                     /* Display serial assignment                */
  WIN: <S0IN >S0OUT         /* S0IN provides serial input &             */
                            /* S0OUT provides serial output             */
>ASSIGN WIN <S1IN >S1OUT    /* Assign S1IN & S1OUT to the Serial window */
>ASSIGN                     /* And display the assignment               */

>ASSIGN COM1 < SIN > SOUT   /* Assign SIN & SOUT to COM1                */


  • The ASSIGN command cannot be used in target mode when the µVision3 debugger talks to hardware drivers.
  • The baudrate and other serial port parameters are set with the MODE command.

  • The PC serial port (COM port) supports only up to 8 data bits. Therefore it is impossible to generate more then 8 data bits as it is possible on some microcontroller UART interfaces.
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