XRT79L71_1 Datasheet, PDF (199/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

REV. 1.0.0
XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
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 Receive DS3/E3 Framer block.
Since the PMON Register (within the Receive DS3/E3 Framer
block) are 16-bit registers. Therefore, given that the bi-direc-
tional data bus of the XRT79L71 is only 8-bits wide, it will require
two read operations in order to read out the entire 16 bit content
of these registers.
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, the user is suppose to obtain the contents of the other byte,
by reading the contents of this register.
One Second Error Status Register (Address = 0x116D)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
Unused
R/O
R/O
R/O
R/O
R/O
0
0
0
0
0
BIT 2
R/O
0
BIT 1
Errored
Second
R/O
0
BIT 0
Severe
Errored
Second
R/O
0
BIT NUMBER
NAME
7-2
Unused
TYPE
R/O
DESCRIPTION
190