Purpose: Serial - send SA after LISTEN
Call address: $FF93 (hex) 65427 (decimal)
Registers: .A = SA (secondary address) Memory: system map Flags: none Calls: LISTENResults:
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).
LDA #8 JSR $FF81 ;LISTEN device 8 LDA #15 JSR $FF93 ;pass it SA # 15