Function Name: SECOND

Purpose: Serial - send SA after LISTEN
Call address: $FF93 (hex) 65427 (decimal)
Preparation:

	Registers:	.A = SA (secondary address)
	Memory:		system map
	Flags:		none
	Calls:		LISTEN

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

Description: SECOND is a low-level serial routine used to send a secondary address (SA) to a LISTENing device (see LISTEN Kernal call). An SA is usually used to provide setup information to a device before the actual data I/O operation begins. Attention is released after a call to SECOND. SECOND is not used to send an SA to a TALKing device (see TKSA). (Most applications should use the higher level I/O routines: see OPEN and CHKOUT).

EXAMPLE:

	LDA	#8
	JSR	$FF81	;LISTEN device 8
	LDA	#15
	JSR	$FF93	;pass it SA # 15