XRT8001 Datasheet, PDF (4/48 Pages) Exar Corporation – WAN Clock for T1 and E1 Systems

XRT8001
PIN DESCRIPTION (CONT'D)
Pin #
8
Name
MSB
9
GND
10
VCC
11
LOCKDET
12
VCC
13
CLK2
14
GND
15
VCC
16
SDI
17
CS
18
SCLK
Type
I
-
-
O
-
O
-
-
I
I
I
Description
Master/Slave Mode Select Input - Setting this input pin “HIGH”
configures the XRT8001 to operate in the “MASTER” Mode. Conversely,
setting this input pin “LOW” configures the XRT8001 to operate in the
“SLAVE” Mode.
Analog Ground
Analog Power Supply
Lock Detect Output - This output indicates whether or not the “selected”
internal PLL(s) are “in-lock” or are “out-of-lock”.
By default, this output pin is “high” when both PLLs are in-lock” and will
go toggle “low” if either one of the PLLs is “out-of-lock”.
However, the XRT8001 also permits the user to configure this output pin
to reflect the state of any one of the PLLs within the chip. (See Table 3.)
Digital Power Supply
Clock Output 2 - The XRT8001 will drive the desired “synthesized”
signal via this output pin. This output signal will have a 50+5% duty
cycle.
Note: This output pin is tri-stated unless the “CLK1EN” bit-field (within
Command Register CR4) has been set to “1”.
Digital Ground
Digital Power Supply
Microprocessor Serial Interface – Serial Data Input
Whenever, the user wishes to read or write data into the Command
Registers, over the Microprocessor Serial Interface, the user is expected
to apply the “Read/Write” bit, the Address Values (of the Command
Registers) and Data Value to be written (during “Write” Operations) to
this pin.
This input will be sampled on the rising edge of the SCLK pin (pin 18).
Microprocessor Serial Interface – Chip Select Input:
The Local Microprocessor must assert this pin (e.g., set it to “0”) in order
to enable communication with the XRT8001 via the Microprocessor
Serial Interface.
Note: This pin is internally pulled “high”.
Microprocessor Serial Interface-Clock Signal
This signal will be used to sample the data, on the SDI pin, on the rising
edge of this signal. Additionally, during “Read” operations, the
Microprocessor Serial Interface will update the SDO output on the falling
edge of this signal.
Rev. 1.01
4