XRT72L71 Datasheet, PDF (10/102 Pages) Exar Corporation – DS3 ATM UNI/CLEAR CHANNEL FRAMER

XRT72L71
DS3 ATM UNI/CLEAR CHANNEL FRAMER
REV. 1.1.0
PIN DESCRIPTION (CONTINUED)
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PIN NO.
13
SYMBOL
D9
14
D8
15
VDD
16
D7
17
D6
18
D5
19
D4
20
Width16
21
D3
22
EncoDis
23
D2
TYPE
I/O
I/O
***
I/O
DESCRIPTION
Bi-Directional Data bus (Microprocessor Interface Section): This pin is
inactive if the Microprocessor Interface block is configured to operate over an
8 bit data bus. Please see description for D15, pin1.
Bi-Directional Data bus (Microprocessor Interface Section): This pin is
inactive if the Microprocessor Interface block is configured to operate over an
8 bit data bus. Please see description for D15, pin1.
Power Supply Pin
Bi-Directional Data bus (Microprocessor Interface Section):
Please see description for D15, pin 1.
I
Microprocessor Interface Block Data Bus Width Selector: This input pin
permits the user to configure the microprocessor interface of the UNI/Framer,
to operate over either an 8 or 16 bit wide bi-directional data bus. Tying this pin
to VDD configures the Microprocessor Interface Data Bus width to be 16 bits.
Tying this pin to GND configures the Microprocessor Interface Data Bus width
to be 8 bits.
I/O Bi-Directional Data bus (Microprocessor Interface Section):
Please see description for D15, pin 1.
O Encoder (B3ZS) Disable Output pin (intended to be connected to the
XRT7300 E3/DS3/STS-1 LIU IC): This output pin is intended to be connected
to the EncoDis input pin of the XRT7300 LIU IC. The user can control the state
of this output pin by writing a “0” or “1” to Bit 3 (EncoDis) of the Line Interface
Driver Register (Address = 0x72). If the user commands this signal to toggle
“High” then it will disable the B3ZS encoder circuitry within the XRT7300 IC.
Conversely, if the user commands this output signal to toggle “Low”, then the
B3ZS Encoder circuitry, within the XRT7300 IC will be enabled.
Writing a “1” to Bit 3 of the Line Interface Driver Register (Address = 0x72) will
cause this output pin to toggle “High”. Writing a “0” to this bit-field will cause
this output pin to toggle “Low”.
NOTES:
1. The user is advised to disable the B3ZS encoder (within the XRT7300
IC) if the Transmit and Receive DS3 Framers (within the UNI) are con-
figured to operate in the B3ZS line code.
2. If the designer is not using the XRT7300 DS3/E3/STS-1 Line Trans-
mitter IC, then output pin can be used for other purposes.
I/O Bi-Directional Data bus (Microprocessor Interface Section):
Please see description for D15, pin1.
6