Storage
Solutions
Serial ATA II
1:4 Port Multiplier Solution
88SM4140
PRODUCT OVERVIEW
The Marvell
簍
88SM4140 port multiplier device offers the industry脮s first solution for port expansion. The device
enables one active host connection to communicate with up to 4 Serial ATA disk drives. The device uses Marvell脮s
production-proven Serial ATA PHY technology and supports both 1.5 Gbps and 3.0 Gbps speeds with adjustable
pre-emphasis and amplitude settings on all 5 ports (1 host, 4 device) for tuning high-speed, long-trace backplane
implementations. The device also provides one Storage Enclosure Management Bridge (SEMB) port for communication
with a Storage Enclosure Processor (SEP). Per the Serial ATA II specification, the 88SM4140 device supports
command-based and FIS-based switching supporting simultaneous queued operations to all attached devices.
The 88SM4140 product also supports a Marvell-proprietary mode called queued command based switching which
enables the performance advantages of FIS-based switching but with reduced complexity.
Host PHY
UART/SEMB
UART
Control
SEMB
Control
Port Arbiter
Serial ATA
Host
MUX
PLL
PM_CTRL
FIFO
REFCLK
Port 0 PHY
Serial ATA
Device 0
Port 1 PHY
Serial ATA
Device 1
Port 2 PHY
Serial ATA
Device 2
Port 3 PHY
Serial ATA
Device 3
Fig 1. Serial ATA II Port Multiplier (88SM4140) Block Diagram
FEATURES
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1.5/3.0 Gbps PHY operation
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FIS-based switching
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Queued command-based switching (Marvell Proprietary)
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1 SEMB port
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Staggered HDD spin-up
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SATA BIST over host and device links
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Programmable pre-emphasis and amplitude per port
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Spread Spectrum Clocking (SSC)
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1.2V and 3.3V power
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Compatible with Marvell 88SX60xx Serial ATA II host controllers
and 88SA8040 Parallel ATA to Serial ATA bridges
BENEFITS
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Supports next-generation HDD designs
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Superior performance by allowing the host to have outstanding
commands to multiple devices at any point in time
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Allows performance advantages of FIS-based switching but with
reduced complexity
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Allows connection to off-chip SEP for enclosure
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Allows host-side control of HDD spin-up to manage power budget
during system power-up
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Enable optimal per-port PHY tuning for Serial ATA backplane designs
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Reduces EMI for enterprise storage and server applications
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Reduces EMI for enterprise storage and server applications
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Interface flexibility
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End-to-end system interoperability
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