.B - Select the Communications Port and Speed

Select the communications port and speed.

Syntax:

──── .B ───────── speed ────┬──────────┬──────────────────────
                              └── port ──┘

Parameters:

speed

The COMx port speed. Any of the following values are valid:

150t

300t
600t
1200t
2400t
4800t
9600t
19200t
Note: Since baud rates are usually expressed in decimal and the default number base for the Kernel Debugger is hexadecimal then a t subscript must be supplied when using decimal values.
port
Specifies which COM port is to be used. If 1 or 2 are specified then COM1 or COM2 are implied. Any other numeric value is assumed to be an I/O port address.

Results & Notes:

When the Kernel Debugger initialises a default baud rate of 9600t is set.

The COM port defaults to COM2 if there are two serial ports otherwise COM1 unless no comports are defined in the ROM BIOS data area, in which case the first port address in the ROM BIOS data area is assumed.

The parity, data and stop bit settings default to none, 8 and 1. These may be altered either:

from the Kernel Debugger by writing directly to the COM port control register using the O command or from the system under test by using the MODE command.

If synchronisation is lost with the debugging console, for example because the debugging communications port has been temporarily used by another application then it may be reset using the MODE command. from the command line of the system under test. For example, to re-specify the default parameters use:

MODE COM2 9600,n,8,1

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