XRT91L32
xr
STS-12/STM-4 OR STS-3/STM-1 SONET/SDH TRANSCEIVER
REV. 1.0.3
4
PIN DESCRIPTIONS
L32
HARDWARE CONTROL
NAME
LEVEL
TYPE
PIN
DESCRIPTION
RESET
LVTTL
I
4
Remote Serial Loopback
Active "High." When this pin is pulled "High" , the internal state
machines are set to their default state.
"Low" = Normal Operation
"High" = Master Hardware Reset ( minimum 100nS)
STS12/STS3
LVTTL
I
97
Data Rate Selection
Selects SONET/SDH transmission and reception speed rate
"Low" = STS-3/STM-1 155.52 Mbps
"High" = STS-12/STM-4 622.08 Mbps
CMUFREQSEL
LVTTL
I
8
Clock Multiplier Unit Reference Frequency Select
This pin is used to select the frequency of the REFCLKP/N or
TTLREFCLK input to the CMU.
"Low" = 77.76 MHz reference clock
"High" = 19.44 MHz reference clock
NOTE: REFCLKP/N or TTLREFCLK input should be generated
from an LVPECL/LVTTL crystal oscillator which has a
frequency accuracy better than 20ppm in order for the
transmitted data rate frequency to have the necessary
accuracy required for SONET systems..
CMU-
FREQSEL
STS12/
STS3
REFCLKP/N OR
TTLREFCLK
REFERENCE
FREQUENCY
DATA RATE
00
77.76 MHz
STS-3/STM-1
155.52 Mbps
0
1
77.76 MHz
STS-12/STM-4
622.08 Mbps
10
19.44 MHz
STS-3/STM-1
155.52 Mbps
1
19.44 MHz
STS-12/STM-4
622.08 Mbps