Cirrus Logic CDB6422 - Manual (Page 6)

CDB6422
6 DS295DB2
2.2.4 Network Output
2.2.4.1 NOUT1:
NOUT1 selects between the “ACTIVE” drive out-
put circuitry (op-amps) and the “PASSIVE” cir-
cuitry (simple RC-network). To take advantage of
the supplied filters and gain stages, set NOUT1 to
the “ACTIVE” state.
2.2.4.2 NOUT2:
NOUT2 selects the order of the Butterworth filter
following NO at either "1-POLE" or "3-POLES".
2.2.4.3 NOUT3, NOUT4:
NOUT3 and NOUT4 select the type and amount of
gain for the network output circuitry. For fixed
gains (NOUT4 = “0dB” or “USER”), NOUT3
should be set to "FIXED". For variable gain (-
20dB to +20dB) NOUT3 should be set to "VARI-
ABLE" and NOUT4 should be set to "-20dB to
+20dB". The pot labeled "NOUT_GAIN" (R4)
controls the variable gain.
2.2.4.4 NOUT5:
NOUT5 selects the source of the network output
RCA jack (“0dB” before gain stage, “GAINED”
after gain stage, or ”PASSIVE” RC-network).
2.2.4.5 NOUT6:
NOUT6 selects the type of output (“AC”-coupled
or “DC”-coupled) at the NOUT_RCA jack.
2.3 CODEC Configuration
The codec is accessible only if the board is operat-
ing from a +12V power supply.
The CDB6422 has a
µ-law/a-law PCM interface
that is accessible through the PCM header
(HDR49). HDR27 enables optional signal inver-
sions for PCM_IN (RDI), PCM_OUT (TDI), CLK
(CI), and SYNC (SI). To enable the inverter, install
the header next to the appropriate label.
To select "a-law" data, install HDR53 (A-LAW).
To power down the codec, install HDR54 (PDI).
2.4 DAA Configuration
To enable DTMF tones to be transmitted to the an-
alog telephone network, HDR86 (DTMF_TX)
must be installed.
2.5 Microcontroller Configuration
2.5.1 PROGRAM/RUN:
The microcontroller is shipped preprogrammed
from the factory. The configuration jumper should
be loaded on HDR94 "RUN". To program the mi-
crocontroller with new software, the configuration
jumper should be moved to HDR91 "PROGRAM"
when the programming software prompts to do so.
2.5.2 EXT/UC:
By default, the microcontroller writes configura-
tion information to the CS6422 through the
CS6422 uC interface. The microcontroller outputs
can be disabled by moving the jumper from
HDR90 (uC) to HDR89 (EXT) to allow an external
source to configure the CS6422 through the "6422
EXT INTERFACE" header (HDR21).
2.5.3 UC_RESET:
The UC_RESET pushbutton initiates a hardware
microcontroller reset. The microcontroller pro-
grams Configuration 0 to the default CS6422 regis-
ter state. It leaves the other Configuration sets
alone. Furthermore, the UC_RESET initiates a
CS6422 reset which performs a hardware reset and
downloads Configuration 0 to the CS6422.
2.6 Miscellaneous
2.6.1 HOOK SWITCH:
Sliding the HOOK SWITCH to “OFF_HOOK”
will cause the DAA to move to the OFF HOOK
state (pick up the phone). Sliding the switch to
“ON-HOOK” will cause the DAA to hang up (after
about a 1 second delay). The uC software automat-
ically answers the phone after 3 rings. To hang up