Avago Technologies LSI53C1010R - Manual (Page 54)

2-24 Functional Description
Version 2.2 Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
To indicate DT or ST mode, a bit is set in the current “selection” data
reserved byte. BMOVE instructions identify the current BMOVE as either
DT or ST through the phase bits.
2.2.5.2 Parallel Protocol Request
CRC, Sync/Wide, DT, Quick Arbitration and Selection (QAS), and
“information units” are negotiated with a new SCSI extended message:
Table 2.3 New Phases on SCSI Bus
Phase MSG C/D I/O Description
ST Data-Out 0 0 0 –
ST Data-In 0 0 1 –
DT Data-Out 1 0 0 Previously reserved
DT Data-In 1 0 1 Previously reserved
Byte 0 0x01 Extended message
Byte 1 0x06 Length
Byte 2 0x04 Parallel Protocol Request (PPR)
Byte 3 0xXX Transfer Period Factor
Byte 4 0x00 Reserved
Byte 5 0xXX Req/ACK Offset
Byte 6 0xXX Transfer Width Exponent
Byte 7 0x0X Protocol options