LSI53CF92A LSI, LSI53CF92A Datasheet - Page 30
LSI53CF92A
Manufacturer Part Number
LSI53CF92A
Description
Manufacturer
LSI
Datasheet
1.LSI53CF92A.pdf
(158 pages)
Specifications of LSI53CF92A
Lead Free Status / RoHS Status
Not Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LSI53CF92A
Manufacturer:
RENESAS
Quantity:
2 381
Part Number:
LSI53CF92A
Manufacturer:
LSI/SYMBIOS
Quantity:
20 000
- Current page: 30 of 158
- Download datasheet (2Mb)
2.5.3 Threshold Eight Mode
2-10
Normal DMA mode tends to monopolize the DMA bus, and slows the
entire system down to the performance level of the SCSI device to which
the chip is connected. In single-threaded systems, however, this remains
the most efficient method of transferring data as long as important
events, like DRAM refresh, can interrupt the DMA transfer.
Figure 2.1
DBWR/
Threshold Eight mode causes the FSC to wait until eight bytes or more
can be transferred before it requests service from the external DMA
controller. Because the DMA bus can operate at speeds five to ten times
greater than typical SCSI devices, this mode allows SCSI operations to
run effectively in parallel with other processes.
The Threshold Eight bit in
the threshold to eight bytes. Refer to the description for the
Configuration 3 (Config 3)
Eight mode is enabled by setting bit 0 in the
register and is valid in both bus configurations. Threshold Eight mode
operates only during SCSI Data In or Data Out phase.
Threshold Eight mode causes DREQ to remain false until the FIFO can
accommodate an eight-byte transfer. This improves DMA bus efficiency
by keeping the chip off this bus until it can transfer at least eight bytes.
With Threshold Eight enabled, the chip retains control of the DMA
channel as long as one transfer can be accommodated. The transfer
continues in normal mode whenever the Transfer Counter drops below
eight bytes and the threshold drops to one transfer.
Functional Description
Copyright © 1995–2002 by LSI Logic Corporation. All rights reserved.
DBRD/
DACK/
DREQ
or
Note:
Normal DMA Mode
When enabling this mode, the synchronous data offset can
only be set to seven or less.
register in
Configuration 3 (Config 3)
Chapter 4, “Registers.”
Configuration 3 (Config 3)
register changes
Threshold
Related parts for LSI53CF92A
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
BGA 117/RESTRICTED SALE - SELL LSISS9132 INTERPOSER CARD FIRST (CONTACT LSI
Manufacturer:
LSI Computer Systems, Inc.
Part Number:
Description:
Keypad programmable digital lock
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
TOUCH CONTROL LAMP DIMMER
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
32bit/dual 16bit binary up counter with byte multiplexed three-state outputs
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
24-bit quadrature counter
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Quadrature clock converter
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Quadrature clock converter
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
Enclosure Services Processor
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
24-bit dual-axis quadrature counter
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
LSI402ZXLSI402ZX digital signal processor
Manufacturer:
LSI Computer Systems, Inc.
Datasheet:
Part Number:
Description:
24 Bit Multimode Counter
Manufacturer:
LSI Computer Systems, Inc.
Datasheet: