XRT8001 Datasheet, PDF (27/48 Pages) Exar Corporation – WAN Clock for T1 and E1 Systems

XRT8001
Q x 2.048MHz
Where: 1 < Q < 16
FIN
CLK1
1.544MHz
XRT8001
WA^XN^RC^T8lo⁰⁰c¹k
CLK2
1.544MHz
Figure 16. Illustration of the XRT8001 WAN Clock
Operating in the “E1 to T1 – Forward/Master” Mode
6.5 Configuring the XRT8001 WAN Clock into the
“E1 to T1 – Forward/Master” Mode
This step configures the XRT8001 WAN Clock to
operate in the “E1 to T1 – Forward/Master” Mode.
The user can configure the XRT8001 WAN Clock to
operate in the “E1 to T1 – Forward/Master” Mode by
executing the following steps:
Note: If the user wishes to output a clock signal via the
CLK1 output signal, then he/she should also write a “1”
into the “PL1EN” bit-field within Command Register,
CR0.
Step 1 – Configure the XRT8001 to operate in the
“MASTER” Mode, by pulling the “MSB” input pin (pin 8)
to VDD.
Step 2 – Write the binary value “1000” into Command
Register CR0, as illustrated below:
Step 3 – Next, you need to specify the value for “Q”
*(e.g., as in the “Q x 2.048MHz” clock signal which
will be applied to the “FIN” input pin).
The user accomplishes this writing the binary
expression for “Q - 1” into Command Register, CR1,
as illustrated below.
Command Register CR0 (Address = 0x00)
D4
D3
D2
D1
D0
IOC4 IOC3
IOC2
IOC1 PL1EN
1
0
0
0
X
Command Register, CR1 (Address = 0x01)
D4
D3
D2
D1
D0
M4
M3
M2
M1
PL2EN
Value of “Q - 1” (in Binary Format)
X
Rev. 1.01
27