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January 24, 2005
CODEC Measurement Set-up
Test access to the CODEC digital I/O is provided by
connectors J10, J11, J12, and J13. Test access to the
CODEC analog ports is provided by inserting jumper JP4 to
connect the VREC connector to the CODEC analog Rx
output, and by inserting jumper JP15 to the correct Tx gain
setting for the CODEC under test. The RSLIC should be
removed during CODEC testing otherwise unwanted loading
of the CODEC analog Tx input signal could result. This set-
up is summarized in Table 8.
CODEC Measurement Capability
The user should refer to the device data sheet for correct
parameter values.
CODEC measurements include:
1. CODEC supply current (RSLIC removed).
2. A-D, D-A gain and frequency parameters.
3. A-law, mu-law companding measurements (JP8).
4. Power down measurements (JP9).
TABLE 3. EVALUATION BOARD CONNECTOR DESCRIPTIONS
CONNECTOR
DESCRIPTION
J1
RJ11 type phone connector.
J2
Ring terminal of board.
J3
Tip terminal of board.
J4
Grounding lug connected to board ground plane.
J5
1: V
CC
. Positive 5V supply to CODEC, RSLICU6, clock generator and logic devices (red wire).
2: V
BH
. High negative battery supply to the HC55185 device (orange wire).
3: V
BL
. Low negative battery supply to the HC55185 device (yellow wire).
4: +5V. Positive 5V supply to the RSLIC LED detector output indicators (green wire).
7 thru 10: GND. Twisted pair returns for external supply connections (black wires).
J6
Identical pinout as J5. Either connector provides daisy chain connection to second board for back to back evaluation.
J7
Transmit analog output from the RSLIC device, VTX. This path is AC coupled and can be used to measure G2-4W of the RSLIC.
The A-D Tx path of the CODEC can be measured using VTX as the signal input, but the RSLIC must be removed due to the
loading effect of the low impedance VTX output.
J8
Receive analog input to the RSLIC, VREC. This path is AC coupled and can be used to measure G4-2W of the RSLIC. Jumper
JP4 must be removed to disconnect the low impedance CODEC output. J8 can also be used to measure the D-A Rx gain of the
CODEC by re-inserting jumper JP4.
J9
Ringing input to HC55185 device, VRS. This path is AC coupled by C
RS
.
J10
Serial transmit data output of CODEC U6.
J11
Serial receive data input to CODEC U6.
J12
Common frame sync input for receive and transmit digital data.
J13
Common clock for CODEC data transfer and conversion.
J14
20 pin, 100 mil spacing header with all digital PCM data interfaces to CODEC U6.
J15
20 pin, 100 mil spacing header with all digital interfaces to the RSLIC.
Application Note 1168
