Spinpoint M9T Product Manual REV 1.0
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CHAPTER 6 SATA II INTERFACE
6.1 Introduction
The Spinpoint M9T disk drive is equipped with an industry standard SATA Interface fully supports and
enhances PC mass storage requirements. The SATA interface conforms to the Serial ATA standards in Cabling,
in Physical Signals, and in Logical Programming schemes. The Spinpoint M9T disk drive joins the industry
premiere VLSI circuitry with ingenious programming skill that does not compromise performance or
reliability. Seagate integrates and delivers the cutting edge in technology. Samsung Spinpoint M9T SATA class
disk drives are designed to relieve and to enhance the I/O request processing function of system drivers.
6.1.1 SATA Terminology
The following contains some commonly proposed terminology used in SATA
technology.
BACKCHANNEL
-
A term used to describe or refer to the transmit same-side of SATA interface, when
the scope of the paragraph is addressing the receive interface. For example, when discussing the receive
SATA interface on the device side, the term “backchannel” would be used to describe the transmit interface
on the device side.
CHARACTER ALIGNMENT-C
haracter alignment is a receiver action that resets the character boundary
to that of the comma sequence found in the K28.5 control character of the ALIGN primitive, and
establishes Dword synchronization of the incoming serial data stream.
CHARACTER SLIPPING-
Character slipping is the receiver action that realigns the receiver’s clock to
the received bit stream by adding or removing bit times within the characters of the ALIGN primitive.
CODE VIOLATION-
A code violation is an error that occurs in the reception process as a result of (1)
a running disparity violation or (2) an encoded character that does not translate to a valid data or
control character or (3) an encoded character that translates to a control character other than K28.5 or K28.3
in byte 0 of a Dword or (4) an encoded character that translates to any control character (valid or invalid)
in bytes 1-3 of a Dword.
COMMA CHARACTER-
A comma character is a control character, that when encoded, contains
the comma sequence. In Serial ATA the only comma character used is K28.5, and only the ALIGN
primitive contains the comma character. The comma sequence is the first seven bits of the encoded character.
COMMA SEQUENCE-
The comma sequence is a seven-bit sequence of 0011111 or 1100000 in an
encoded stream. The comma sequence is unique in that it appears only in a single encoded character, and
furthermore, cannot appear in any subset of bits in adjacent encoded characters. This unique property
allows the comma sequence to be used for determining alignment of the received data stream.
COMRESET / COMINIT-
Host: Signal from the out of band detector that indicates the COMINIT out
of band signal is being detected.
CONTROL CHARACTER-
A control character is a combination of a byte value with the control
variable equal to K.
CONTROL VARIABLE-
The control variable, Z, is a flag that determines the code set to be used to
interpret a data byte. The control variable has the value D (for data characters) or K (for control characters).
CRC-
In Serial ATA a 32-bit CRC is calculated over the contents of a FIS. The Serial ATA CRC is the Dword in
a frame that immediately precedes the EOF primitive.
