Function Name: UNLSN

Purpose: Serial - send unlisten
Call address: $FFAE (hex) 65454 (decimal)
Preparation:

	Registers:	none
	Memory:		system map
	Flags:		none
	Calls:		none

	Registers:	.A used
	Memory:		STATUS ($90)
	Flags:		none

Description: UNLSN is a low-level Kernal serial bus routine that sends an UNLISTEN command to all serial bus devices. It commands all LISTENing devices to stop reading data. (Most applications should us the higher-level I/O routines; see CLRCHN)

EXAMPLE:

	JSR	$FFAE	;UNLISTEN serial device