Serial ATA (Advanced Technology Attachment)
[SATA Description] [Serial ATA
Jitter] [Interface ICs]
[SATA Connector/Cable] [SATA
Pinout] [PATA]
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The Serial ATA bus [SATA] is the serial version of the IDE [ATA] spec.
SATA uses a 4 conductor cable with two differential pairs [Tx/Rx], plus
an additional three grounds pins and a separate power connector. Data
runs at 150MBps [1.5GHz] using 8B/10B
encoding and 250mV signal swings, with a maximum bus length of 1 meter.
Later SATA enhancements move the data transfer speed to; 300MBps
[3.0Gbps], and then 600MBps [6.0Gbps]. The current speed for SATA is
600Mbps [6Gbps] for version 3.0 of the standard which was released at the end of 2009. Shielded external SATA [eSATA] data cable runs out to a maximum
of between 3 feet and 6 feet. eSATA cables are used external to the
chassis or case. Just released xSATA which is an external interface out to 8 meters. |
The 32-bit CRC polynomial is X32+ X26+ X23+ X22+ X16+ X12+ X11+ X10+ X8+ X7+ X5+ X4+ X2+ X + 1.
SATA Electrical
Serial ATA uses LVDS [EIA/TIA-644]
with voltages of 250mV; while the obsolete parallel ATA interface is based on TTL signaling levels and rates.
Serial ATA is a point-to-point interface where each device is directly
connected to the host via a dedicated link. Because Serial ATA uses a
dedicated link, adding another drive to the computer will have no impact
on bandwidth. With Serial ATA the additional hard drive uses a separate
SATA link, while the older IDE parallel standard [PATA] would see a
degradation in speed because the drives would share the same link band
width. The Bit Encoding used is: Non Return to Zero (NRZ)
encoding for data communication on a differential two wire bus. The use
of NRZ encoding ensures compact messages with a minimum number of
transitions and high resilience to external disturbance. The termination resistor is 100 Ohms [+/- 5 Ohms]
differential.
SATA Physical
Serial ATA uses only 4 signal pins, improving pin efficiency over the
parallel ATA interface which uses 26 signal pins going between devices
[over an 80 conductor ribbon cable onto a 40 pin header connector].
Serial ATA also provides the opportunity for devices to be 'hot-plugged',
devices may be inserted or removed while the system is powered on. The
pinout tables for Serial ATA are listed below.
The primary function of Serial ATA bus is to form an interface between
the Motherboard
and the Hard Disk Drive
[HDD]. The Hard Drive may have a SATA connector and a legacy PATA data connector, with a legacy
PATA power connector, so the
device may function in either a legacy [older] motherboard or a currently
produced motherboard. In this case the mother board S-ATA interface would
be developed from a peripheral add-on board and not the motherboard.
Power connectors on a HDD are header pins for a P-ATA interface and
card-edge finger blades in the case of S-ATA. Some drive connectors
shield the S-ATA power connector preventing their use, so you must use
the P-ATA power pins to supply power to the drive. Terms used to describe
the obsolete Harddrive interface which preceded the SATA interface
include; IDE, Parallel ATA, PATA, and P-ATA.
Deterministic Jitter [DJ], and Total Jitter [TJ] are listed in the table
below. TJ is the addition of DJ and Random Jitter [RJ].
The Driver Output Jitter listed is the maximum allowed jitter from the
driver. The Receiver Input jitter is the maximum jitter the receiver will
tolerate.
Description | Driver Output |
Driver PCB Connector |
Receiver PCB Connector |
Receiver Input |
||||
DJ | TJ | DJ | TJ | DJ | TJ | DJ | TJ | |
A0,p-p(UI) | 0.15 | 0.33 | 0.175 | 0.355 | 0.25 | 0.43 | 0.275 | 0.455 |
n0 | ||||||||
A1,p-p(UI) | 0.2 | 0.45 | 0.22 | 0.47 | 0.35 | 0.6 | 0.37 | 0.62 |
n1 | ||||||||
A2,p-p(UI) | ||||||||
n2 |
The table does not account for UI error due to frequency skew. The final two rows list Total Jitter [TJ] only.
As with any interface, just because the latest revision of SATA runs at 6Gb/s
does not imply that a hard drive interface can sustain that speed.
Serial ATA uses LVDS [EIA/TIA-644] with voltages of 250mV.
Atmel {Serial ATA Bridge IC, PATA to SATA Converter}
Genesys logic {USB 3.0 to SATA 3Gb/s Bridge Controller, SATA to PATA Bridge Controller}
JMicron Technology Corporation {1 to 5-ports Serial ATA II Port Multiplier with RAID function support, PCI Express to SATA II Host Controller}
LSI Corporation {8-Port 3Gbps SATA Controller}
Marvell {Serial ATA Bridge IC, PATA to SATA Converter}
Mixel {Quad Gigabit Transceiver IP}
PLX Technology {FireWire/USB to SATA Controllers, USB to SATA Controllers, Consumer Network Attached Storage (NAS) SoC, Consumer Direct Attached Storage (DAS) SoC}
Silicon Storage Technology, Inc. 'SST' {SATA Disk Controller IC}
Soft Mixed Signal Corporation 'SMS' {SATA PHY transceiver IP}
Another listing of PC Chip Set Manufacturers, Programmable Logic IP Cores
Serial ATA Revision 3.0, 5/2009
Serial ATA: High Speed Serialized AT Attachment; Revision 1.0, 1/2003
Serial ATA: High Speed Serialized AT Attachment; Revision 1a, 8/2001
Serial ATA: Electrical Specification; Revision 1.0, 5/2004
Serial ATA: Specification; Revision 2.6, 3/2007
SATA PHY Interface Specification [SAPIS] Intel
External Serial ATA [eSATA]
T13 {Technical Committee T13; AT Attachment} ...... Serial ATA {Serial ATA Working Group}
The Serial ATA bus is defined over two separate connectors, one for the
data lines and one for the power lines. A Serial ATA Hard drive may also
have a third connector for legacy PATA power
connections. The PATA power connector may be used in instead of the SATA
power to supply a connection which is more rugged and reliable then the
SATA-1 power connection.
Some Solid State Drives [SSD] may not require all of the defined SATA power connections. In addition a Serial ATA Power Adapter Cable my be purchased to transitions from 15-pin SATA power to 4-pin Parallel power connectors [Backwards compatible for standard AT/ATX power supplies].
The pinout for SATA is listed on the SATA Pinout [Signal Assignments]
page.
The cable uses two shielded pairs to carry data. The wire is 26 AWG solid copper wire. The impedance is 100 ohms. Common internal SATA cable lengths are 12, 18, and 36 inches. The internal cables maybe straight both ends or 90 degree. Shielded external SATA [eSATA] data cable run 3 feet or 6 feet. A Cable may also contain both SATA Data and Power combined into an 18inch cable. Illuminated cable is also available. For reference; the older IDE flat cable is five times wider then the new Serial ATA round cable. The smaller Serial ATA cable allows for better air flow within the Personal Computer chassis
Adam Technologies {SATA Connectors, Stacked SATA}
Amphenol {SATA Connector Manufacturer}
BAFO Technologies {SATA - 7 Pin Internal, 7 Pin External with metal Shield, 15 Pin - 4 Pin Housing Power}
Belkin Corporation {Serial ATA Cable 18 inches, 24 inches, 3 foot length, Right Angled, Multi-Colored}
Circuit Assembly {Serial ATA Signal Cable}
DATACOMM Cables Inc {SATA 150, Straight 19"and 39 inch long. 90 degree bend 18" and 36 inch long}
Delphi {Serial ATA Cables}
FCI {SATA Connectors, SATA Cable Assemblies}
Foxconn {Serial ATA, 7/22 positions, SMT/Thru hole Single Row, RoHS}
Hitachi Cable Manchester, Inc. {Serial ATA 4-Conductor PVC Cable, 100 ohm differential Impedance}
Molex {Serial ATA Connectors and Cables Assemblies}
TaiSol Electronics {Serial ATA DIP Connectors, Serial ATA 15P/7P Male Female Connectors and Serial ATA Data Cable, Serial ATA Power Cable}
T-CONN Precision Corp. {SATA}
Tripp Lite {Serial ATA Signal Cable - 39" 7 Pin Straight Female/Female}
Tyco Electronics {Serial ATA 7 Position PCB MT Components, 7 Position Type I/type II Cable Assemblies, 26 AWG Bulk Cables}
PATA information is provided below for reference, how ever with
the addition of SATA ~ PATA is now obsolete, you can refer to the
Parallel ATA bus page for more
information. Serial ATA uses 250mV
switching levels instead of 5 volt TTL levels [reducing power
requirements], a smaller cable [increasing air flow in the chassis],
operates at 150MBps instead of 133MBps, and is Hot-Swappable.
Here is a chart of Hard Drive Transfer Speeds. The chart compares
each version of PATA [ATA-1, ... ATA-7, and the 2 versions of SATA.
Serial ATA is not compatible with the IDE [Parallel ATA]
because the connectors are different, the voltage levels are different,
and SATA sends a bit at a time while PATA sends 16 bits at once. The two
bus types will not interface with one another; PATA will not mate with
SATA. The IDE bus will not connect to the SATA bus. Converter boards are
available which translate Serial ATA to Parallel ATA interfaces for a
cost around 50 dollars.
ATA-1 (IDE), [Obsolete] 8.3MBytes/sec, 8 or 16 bit data width, 40
pin data ribbon cable/connector. With a maximum of 2 devices on the bus.
Using PIO Modes 0, 1 or 2. Performed no bus error correction.
ATA-2 (EIDE, or Fast ATA), [Obsolete] 16.6MBytes/sec, 8 or 16 bit
data width, 40 pin data ribbon cable/connector. With a maximum of 4
devices on the bus. Using PIO Modes 0, 1, 2, 3, or 4
ATA-3, [Obsolete] 16MBytes/sec, 16 bit data width, 40 pin data
ribbon cable/connector. Using PIO Modes 0, 1, 2, 3, or 4 and Multiword
DMA modes 1 and 2. Runs with 120nS Strobes (rising edge to rising edge).
Includes CRC.
ATA-4 Ultra-ATA/33, [Obsolete] 33MBytes/sec, 16 bit data width, 40
pin data ribbon cable/connector. Using PIO Modes 0, 1, 2, 3, or 4 and
Multi-word DMA modes 1 and 2 and Ultra DMA modes 0, 1, and 2. Runs at a
60nS rate, using both edges of a 120nS Strobe.
ATA-5 Ultra-ATA/66, 66MBytes/sec, 16 bit data width 40-pin data
connector/80 pin cable, with the additional 40 pins being Ground. Using
PIO Modes 0, 1, 2, 3, or 4 and Multiword DMA modes 1 and 2 and Ultra DMA
modes 0, 1, 2, 3 and 4. Runs at a 30nS rate, using both edges of a 60nS
Strobe.
ATA-6 Ultra-ATA/100, 100MBytes/sec,16 bit data width 40 pin data
connector/80 pin cable, with the additional 40 new pins being Ground.
Using PIO Modes 0, 1, 2, 3, or 4 and Multiword DMA modes 1 and 2 and
Ultra DMA modes 0, 1, 2, 3, 4 and 5.
ATA-7 Ultra-ATA/133, 133MBytes/sec,16 bit data width 40 pin data
connector/80 pin cable, with the additional 40 new pins being Ground.
Topic Navigation: Engineering Home > Interface Buses > Personal Computer Buses > SATA Description.
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