XRT8001 Datasheet, PDF (23/48 Pages) Exar Corporation – WAN Clock for T1 and E1 Systems

XRT8001
6.0 The “Reverse/Master” Mode
When the XRT8001 WAN Clock has been configured to
operate in the “Reverse/Master” Mode, then it will
accept either a “56kHz” or a “64kHz” clock signal via
the “Reference Clock” input at FIN (pin 3). In response
to this clock signal, the XRT8001 WAN Clock will
output either a “1.544MHz” or a “2.048MHz” clock
signal, via the Clock Output pins (CLK1 and/or CLK2).
A simple illustration of the XRT8001 WAN Clock,
operating in the “Reverse/Master” Mode is presented
in Figure 14.
56kHz
or
64kHz
FIN
CLK1
X_XR_RT_T8₈₀0₀0₁1
W_WA_AN_N C_Cl_loo_cc_kk
CLK2
1.544MHz
or
2.048MHz
1.544MHz
or
2.048MHz
Figure 14. Illustration of the XRT8001 WAN Clock
Operating in the “Reverse/Master” Mode
6.1 Configuring the XRT8001 WAN Clock Device
into the “Reverse/Master” Mode
The user can configure the XRT8001 WAN Clock to
operate in the “Reverse/Master” Mode, by executing
the following steps:
Step 1 – Configure the XRT8001 to operate in the
“MASTER” Mode by pulling the “MSB” pin (pin 8) to
VDD.
Step 2 – Review Table 5, and determine which combi-
nation of “Input Frequency” and “Output Frequencies”
(via PLL1 and PLL2) correlate with the desired configu-
ration.
Rev. 1.01
23