Avago Technologies LSI53C1010 - Manual (Page 259)

Using SCRIPTS for Target Operation 11-9
Figure 11.9 SCRIPTS Source Code–Extended Message
In synchronous negotiation, Figure 11.10 , the SCRIPTS processor
moves synchronous period and offset data from the synchronous
negotiation message and interrupts to set up the synchronous operation
and return message.
Figure 11.10 SCRIPTS Source Code–Synchronous Negotiation
If the extended message indicates wide negotiation, the SCRIPTS
processor expects one more byte with SCSI bus width information, as
shown in
Figure 11.11 . After receiving the byte, it interrupts to set up the
answer.
Figure 11.11 SCRIPTS Source Code–Wide Negotiation
After the interrupt service routine executes, the SCRIPTS processor
sends its return negotiation message. See
Figure 11.12 for an example.
Figure 11.12 SCRIPTS Source Code–Return Negotiation
extended_msg:
int bad_extended_msg, if not atn ;if atn gone, extended message was bad
move from msg_out_buf, with msg_out ;get next message byte
int bad_extended_msg, if not atn ;if atn gone, extended message was bad
move from msg_out_buf, with msg_out ;this byte shows type of message
jump rel(synch_neg), if 0x01 ;0x01 is a synchronous negotiation message
jump rel(wide_neg), if 0x03 ;0x03 is a wide negotiation message
int bad_extended_msg ;interrupt on any other type
synch_neg:
move from synch_neg_msg_out, with msg_out ;move in the period and offset
int set_up_synch_neg ;interrupt to set up synchronous and
;message
wide_neg:
move from wide_neg_msg_out, with msg_out ;move in the width
int set_up_wide_neg ;interrupt to set up answer
synch_wide_neg_return:
move from neg_msg_in, with msg_in ;move out our answer to the negotiation
jump rel(command_phase), if not atn ;jump to command_phase if atn gone
jump rel(msg_out_phase) ;jump to msg_out_phse if atn still active