Avago Technologies LSI53C1000R - Manual (Page 246)

5-4 SCSI SCRIPTS Instruction Set
Version 2.2 Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
Figure 5.1 SCRIPTS Overview
5.2 Block Move Instructions
For Block Move instructions, bits 5 and 4 (SIOM and DIOM) in the
DMA Mode (DMODE) register determine whether the source/destination
address resides in memory or I/O space. When data is moved onto the
SCSI bus, SIOM controls whether that data comes from the I/O or
memory space. When data is moved off of the SCSI bus, DIOM controls
whether that data goes to the I/O or memory space.
5.2.1 First Dword
This section describes the structure of the first SCSI SCRIPTS Dword.
Bits [31:24] are loaded into the DMA Command register while bits [23:0]
are loaded into the DBC register.
System Processor
System Memory
(or Internal RAM)
SCSI Initiator Write Example
select ATN0, alt_addr
move 1, identify_msg_buf, when MSG_OUT
move 6, cmd_buf, when CMD
move 512, data_buf, when DATA_OUT
move 1, stat_in_buf, when STATUS
move 1, msg_in_buf, when MSG_IN
move SCNTL2 & 7F to SCNTL2
clear ACK
wait disconnect alt2
int 10
Data Structure
Message Buffer
Command Buffer
Data Buffer
Status Buffer
LSI53C1000R
SCSI
Bus
Write DSP
Fetch
SCRIPTS
Data
(Data is not fetched across system bus if
internal RAM is enabled.)
System
Bus