XRT79L71 Datasheet, PDF (242/441 Pages) Exar Corporation – 1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

XRT79L71
REV. P1.0.3
PRELIMINARY
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1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
PRBS ERROR COUNT REGISTER - LSB (DIRECT ADDRESS = 0X1169)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
PRBS_Error_Count_Lower_Byte[7:0]
RUR
RUR
RUR
RUR
RUR
RUR
0
0
0
0
0
0
BIT 1
RUR
0
BIT 0
RUR
0
BIT NUMBER
NAME
7-0
PRBS
Error_Count_Lower
Byte[7:0]
TYPE
RUR
DESCRIPTION
PRBS Error Count - Lower Byte:
These RESET-upon-READ bits, along with that within the "PRBS
Error Count Register - MSB" combine to reflect the cumulative
number of PRBS bit errors that have been detected by the Pri-
mary Frame Synchronizer block, since the last read of this regis-
ter.
This register contains the Least Significant byte of this 16-bit
expression.
NOTE: These register bits are not active if the Primary Frame
Synchronizer block has been by-passed, and if the
PRBS Receiver has not been enabled.
PMON HOLDING REGISTER (DIRECT ADDRESS = 0X116C)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
PMON_Hold_Value[7:0]
R/O
R/O
R/O
R/O
R/O
0
0
0
0
0
BIT 2
R/O
0
BIT 1
R/O
0
BIT 0
R/O
0
BIT NUMBER
NAME
7-0
PMON Holding Value
TYPE
R/O
DESCRIPTION
PMON Holding Value:
These READ-ONLY bit-fields were specifically allocated to sup-
port READ operations to the PMON (Performance Monitor) Reg-
isters, within the DS3/E3 Framer blocks.
Since the PMON Register (within the DS3/E3 Framer block) are
16-bit registers. Therefore, given that the bi-directional data bus
of the XRT79L71 is only 8-bits wide, it will require two read oper-
ations in order to read out the entire 16 bit content of these regis-
ters.
The other thing to note is that the PMON Registers (within the
DS3/E3 Framer blocks) are RESET-upon-READ type registers.
As consequence, the entire 16-bit contents of a given PMON
Register will be cleared to "0x0000" immediately after the user
has executed the first (of two) read operations to this register. In
order to avoid losing the contents of the other byte, the contents
of the "un-read" byte is automatically loaded into this register.
Hence, once the user reads a register, from a given PMON Reg-
ister, he/she is suppose to obtain the contents of the other byte,
by reading the contents of this register.
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