LSI53CF92A-64QFP LSI, LSI53CF92A-64QFP Datasheet - Page 108

• Manufacturer Part Number: LSI53CF92A-64QFP
• Manufacturer: LSI

Specifications of LSI53CF92A-64QFP

• Lead Free Status / RoHS Status: Supplier Unconfirmed

5.4.4 Transfer Pad
5.4.5 Set ATN
5.4.6 Reset ATN
5-16
Transfer Pad is usually an error recovery technique. It is useful when a
target requests more bytes than an initiator has to send, or when an
initiator must receive and discard a number of bytes from a target.
When transmitting to the SCSI bus, Transfer Pad fills the FIFO with null
bytes and sends them to the SCSI bus. When receiving from the SCSI
bus, Transfer Pad receives bytes, places them on the top of the FIFO,
and discards them from the bottom of the FIFO.
When sending pad bytes to the SCSI bus, DMA must be enabled. No
DMA requests are actually made, but the FSC uses the transfer counter
to end the transfer.
The command terminates under the same conditions as the
Section 5.4.1, “Transfer Information,”
does not leave ACK/ asserted on the last byte of a Message In phase.
If the command terminates before the transfer counter reaches zero
(due to phase change or disconnect) the FIFO may contain pad bytes.
This command asserts attention on the SCSI bus. No interrupt is generated
from this command. ATN/ stays asserted until the last byte of a message
out phase. This command does not pre-empt a command in progress;
attention is asserted after the current command is completed.
DMA commands use the transfer counter to indicate the last byte. For
non-DMA commands, the last byte means that the FIFO is empty. For
DMA transfers, the last byte means that the transfer counter is zero. ATN/
is also released if the target disconnects prematurely.
This command causes ATN/ to be released. It does not cause an interrupt.
This command must not be used when connected to a device supporting
the Common Command Set (CCS). The FSC obeys CCS protocol by
releasing ATN/ on the last byte of a Message Out phase. The Reset ATN
command is provided for older devices that do not respond properly to
the ATN/ condition.
Command Set
Copyright © 1995–2002 by LSI Logic Corporation. All rights reserved.
command, except that the FSC