HDMP-1012 Datasheet, PDF (25/42 Pages) Agilent(Hewlett-Packard) – 4Low Cost Gigabit Rate Transmit/Receive Chip Set

HDMP-1012 (Tx), HDMP-1014 (Rx)
Operating Modes
M20SEL
FLAGSEL
Description
0
0
16 bit data plus error checking
0
1
16 bit data plus FLAG
1
0
20 bit data plus error checking
1
1
20 bit data plus FLAG
HDMP-1012 (Tx), HDMP-1014 (Rx)
Data Frame Structure
M20SEL Not Asserted (16 bit data mode)
Data Status
Flag bit
D-Field
True
Inverted
True
Inverted
0
D₀ - D₁₅
0
D₀ - D₁₅
1
D₀ - D₁₅
1
D₀ - D₁₅
HDMP-1012 (Tx), HDMP-1014 (Rx)
Data Frame Structure
M20SEL Asserted (20 bit data mode)
Data Status
True
Inverted
True
Inverted
Flag bit
0
0
1
1
D-Field
D₀ - D₁₉
D₀ - D₁₉
D₀ - D₁₉
D₀ - D₁₉
C-Field
1101
0010
1011
0100
C-Field
1101
0010
1011
0100
Control Frame Codes
There are 2¹⁸ control words
provided in 20 bit mode. If the
user desires to send a control
word, his lower 9 bits (D0-D8)
are sent as bits D0-D8 of the D-
Field. The user’s next 9 bits (D9-
D17) are sent as bits D11-D19 of
the D-Field. The control frame is
either inverted or not inverted as
needed to maintain balance, with
the coding bits 0011 used to
indicate true control, and the bits
1100 used to indicate
complement control. The bits d9
and d10 are always forced to 0 1
for true control frames and 1 0
for complement control frames.
These middle bits are used to
distinguish control frames from
fill frames, which always have the
middle bits set to either 00, 11, or
10. Similarly, there are 2¹⁴
control words provided in 16 bit
mode.
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