Line interface pins, Nterface, 6 line interface pins – Rainbow Electronics DS21458 User Manual
Page 27
DS21455/DS21458 Quad T1/E1/J1 Transceivers
27 of 270
Signal Name:
JTCLK
Signal Description:
IEEE 1149.1 Test Clock Signal
Signal Type:
Input
This signal is used to shift data into JTDI on the rising edge and out of JTDO on the falling edge.
Signal Name:
JTDI
Signal Description:
IEEE 1149.1 Test Data Input
Signal Type:
Input
Test instructions and data are clocked into this pin on the rising edge of JTCLK. This pin has a 10k
W pullup resistor.
Signal Name:
JTDO
Signal Description:
IEEE 1149.1 Test Data Output
Signal Type:
Output
Test instructions and data are clocked out of this pin on the falling edge of JTCLK. If not used, this pin should be left
unconnected.
5.6 Line Interface Pins
Signal Name:
MCLK1
Signal Description:
Master Clock Input for Transceivers 1 and 2
Signal Type:
Input
A (50ppm) clock source. This clock is used internally for both clock/data recovery and for the jitter attenuator for both T1 and
E1 modes. The clock rate can be 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz. When using the DS21455/DS21458 in
T1-only operation a 1.544MHz (50ppm) clock source can be used. MCLK1 and MCLK2 can be driven from a common clock.
Signal Name:
MCLK2
Signal Description:
Master Clock Input for Transceivers 3 and 4
Signal Type:
Input
A (50ppm) clock source. This clock is used internally for both clock/data recovery and for the jitter attenuator for both T1 and
E1 modes. The clock rate can be 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz. When using the DS21455/DS21458 in
T1-only operation a 1.544MHz (50ppm) clock source can be used. MCLK1 and MCLK2 can be driven from a common clock.
Signal Name:
LIUC/TPD (DS21455), TPD (DS21458)
Signal Description:
Line Interface Unit Connect/Transmit Power-Down
Signal Type:
Input
This is a dual function pin depending on the state of the LTS bit in the LBCR register (LBCR.7).
LTS = 0: In this mode the LIUC/TPD pin, along with the LIUC bit of the LBCR register controls the connection between the
framer and the LIU. This function is only available on the DS21455. See the LIUC bit description in Section
and
LTS = 1: In this mode the LIUC/TPD pin along with the TPD bit in the LIC1 register (LIC1.0) controls the state of the
Transmit Power-Down function. See the TPD bit description in Section
and
Signal Name:
RTIP and RRING
Signal Description:
Receive Tip and Ring
Signal Type:
Input
Analog inputs for clock recovery circuitry. These pins connect via a 1:1 transformer to the network. See Section
for details.
Signal Name:
TTIP and TRING
Signal Description:
Transmit Tip and Ring
Signal Type:
Output
Analog line-driver outputs. These pins connect via a 1:2 step-up transformer to the network. See Section
for details.