CDB61581 Datasheet, PDF (6/16 Pages) Cirrus Logic – Universal Line Interface Unit

CDB61581
10. EVALUATION HINTS
1) The orientation of pin 1 for the CS61581 is
marked by a small circle on the top-left side of
the socket U1.
2) Component locations R1-R2, R3-R4, Y1, T1
and T2 must have the correct values installed
according to the application. All the necessary
components are included with the evaluation
board.
3) Closing a DIP switch on SW1 away from the
label sets the CS61581 control pin of the same
name to logic 1.
4) When performing a manual loopback of the re-
covered signal to the transmit signal at the BNC
connectors, the recovered data must be valid on
the falling edge of RCLK to properly latch the
data in the transmit direction.
5) Jumpers can be placed on header HDR4 to pro-
vide a ground reference on TRING for 75 Ω
coax E1 applications.
Properly terminate TTIP/TRING when evaluating
the transmit output pulse shape. For more informa-
tion concerning pulse shape evaluation, refer to the
Crystal application note entitled "Measurement and
Evaluation of Pulse Shapes in T1/E1 Transmission
Systems."
Jumper Position
Junction Selected
HDR1-2
MATZ
Selects matched impedance, connecting TTIP/TRING directly to the transformer
LOWZ Selects low impedance, connecting TTIP/TRING to the transformer through R4/R3
HDR3
X
Don’t care (not populated)
HDR4
IN
Grounds TRING on the line side of the transmit transformer
HDR5
IN
Grounds the line side of RRING through C2
HDR6
INT
Host Mode operation, connects INT pin to the serial interface
NLOOP_LE Hardware Mode operation, connects NLOOP pin to the LED
D
HDR7
GND
Grounds the MCLK pin
MCLK Connects the MCLK pin to the BNC
HDR8
IN
Pulls the TNEG pin high, for selecting the coder mode (TCLK has to be present for
selecting the coder mode)
HDR9
XTAL-HI Pulls the pin XTALIN high
XTAL-GND Pulls the pin XTALIN to ground
HDR10
X
Don’t care (shorted)
HDR11
OUT
Allows S2 to pull RLOOP and LLOOP high for RESET in hardware mode
IN
Allows S2 to pull RLOOP, LLOOP, and TAOS high for enabling NLOOP in hardware
mode
HDR12
X
Provides access to the serial port signals
Table 3. Jumper Selections
6
DS211DB2