Purpose: Send secondary address for LISTEN
Call address: $FF93 (hex) 65427 (decimal)
Communication registers: A
Preparatory routines: LISTEN
Error returns: See READST
Stack requirements: 8
Registers affected: A
Description: This routine is used to send a secondary address to an I/O device after a call to the LISTEN routine is made, and the device is commanded to LISTEN. The routine canNOT be used to send a secondary address after a call to the TALK routine.
A secondary address is usually used to give setup information to a device before I/O operations begin.
When a secondary address is to be sent to a device on the serial bus, the address must first be ORed with $60.
How to Use:
;ADDRESS DEVICE #8 WITH COMMAND (SECONDARY ADDRESS) #15 LDA #8 JSR LISTEN LDA #15 JSR SECOND