
DS3171/DS3172/DS3173/DS3174
35 of 230
PIN NAME
TYPE
PIN DESCRIPTION
JTMS
Ipu
JTAG Mode Select (with pull-up)
JTMS
: This input signal is used to control the JTAG controller state machine and is
sampled on the rising edge of JTCLK.
JTAG Data Input (with pull-up)
JTDI
: This input signal is used to input data into the register that is enabled by the
JTAG controller state machine and is sampled on the rising edge of JTCLK.
JTAG Data Output
JTDO
: This output signal is the output of an internal scan shift register enabled by the
JTAG controller state machine and is updated on the falling edge of JTCLK. The pin
is in the high impedance mode when a register is not selected or when the
JTRST
signal is high. The pin goes into and exits the high impedance mode after the falling
edge of JTCLK
JTAG Reset (active low with pullup)
JTRST
: This input forces the JTAG controller logic into the reset state and forces the
JTDO pin into high impedance when low. This pin should be low while power is
applied and set high after the power is stable. The pin can be driven high or low for
normal operation, but must be high for JTAG operation.
JTDI
Ipu
JTDO
Oz
JTRST
Ipu
CLAD
CLKA
I
Clock A
CLKA
: This clock input is a DS3 signal(44.736MHz +/-20ppm) when the CLAD is
disabled or it is one of the CLAD reference clock signals when the CLAD is enabled.
Clock B
CLKB
: This pin is a E3(34.368 MHz +/-20 ppm) input signal when the CLAD is
disabled or it can be enabled to output a generated clock when the CLAD is enabled.
The pin is driven low when it is not selected to output a clock signal and the CLAD is
enabled. Refer to
Table 10-11
.
Clock C
CLKC
: This pin is a STS-1 (51.84 MHz +/-20ppm) input signal when the CLAD is
disabled or it can be enabled to output a generated clock when the CLAD is enabled.
The pin is driven low when it is not selected to output a clock signal and the CLAD is
enabled. Refer to
Table 10-11
.
POWER
Ground, 0 Volt potential
Common to digital core, digital IO and all analog circuits
Digital 3.3V
Common to digital core and digital IO
Analog 3.3V for receive LIU on port n
Powers receive LIU on port n
Analog 3.3V for transmit LIU on port n
Powers transmit LIU on port n
Analog 3.3V for jitter attenuator on port n
Powers jitter attenuator on port n
Analog 3.3V for CLAD
Powers clock rate adapter common to all ports
CLKB
IO
CLKC
IO
VSS
PWR
VDD
PWR
AVDDRn
PWR
AVDDTn
PWR
AVDDJn
PWR
AVDDC
PWR