XRT8001 Datasheet, PDF (29/48 Pages) Exar Corporation – WAN Clock for T1 and E1 Systems

XRT8001
64kHz
M x 2.048MHz
FIN
CLK1
M = 1, 2, 4 or 8
XRT8001
WAN Clock
CLK2
M x 2.048MHz
M = 1, 2, 4 or 8
Figure 17. Illustration of the XRT8001 WAN Clock
Operating in the “High Speed – Reverse” Mode
6.7 Configuring the XRT8001 WAN Clock into the
“High Speed – Reverse” Mode.
The user can configure the XRT8001 WAN Clock to
operate in the “High Speed – Reverse” Mode, by
executing the following steps.
Step 3 – Write the binary expression “0000” into bit-
fields “D4 through D1” within Command Register, CR1,
as illustrated below.
Step 1 – Configure the XRT8001 to operate in the
“SLAVE” Mode, by pulling the “MSB” input pin (pin 8)
to GND.
Step 2 - Write the value "1101" into bts D4-D1 within
command register CR0
Command Register CR0 (Address = 0x00)
D4
D3
D2
D1
D0
IOC4 IOC3 IOC2 IOC1 PL1EN
1
1
0
1
X
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.
This step configures the XRT8001 to operate in the
“High Speed – Reverse” Mode.
Rev. 1.01
Command Register, CR1 (Address = 0x01)
D4
D3
D2
D1
D0
M4
M3
M2
M1 PL2EN
0
0
0
0
1
Note: If the user wishes to output a clock signal via the
CLK2 output signal, then he/she should also write a “1” into
the “PL2EN” bit-field within Command Register CR1.
Step 4 – Specify the value for “M” (e.g., as in the “M x
2.048MHz” clock signal) which is to be output via the
“CLK1” output pin.
This is accomplished by reviewing Table 7, and deter-
mining the 5 bit binary value which corresponds with
the desired value of “M”. Afterwards, the user should
write this value into Command Register CR2.
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