DS1113F1
49
CS4399
5.4 Alert Mixing Shutdown
2. Power up and verify communication with CS4399. If there is no communication, it is possible that the crystal did
not start. Check power rails and load capacitance and try again.
3. Clear PDN_CLKOUT in the Power Down Control (0x20000) register. This sets the clock output at MCLK_INT/2
frequency from CLKOUT pin.
4. Measure the frequency and verify that it is within acceptable range of the desired frequency. If yes, continue
normal operation. If not, power down the chip, change the load capacitor values and go back to step 2.
Note:
These steps need to be performed only once per PCB.
5.4 Alert Mixing Shutdown
To prevent a DSD mute pattern from turning off the DAC while mixing DSD data with PCM data, turn off the auto mute by
clearing the
bit.
5.5 Enable/Disable Nonoversampling Filter
If the user decides to use the nonoversampling filter, the following sequences must be followed to enable/disable the
nonoversampling filter.
5.5.1
Nonoversampling Filter Enable Sequence
5.5.2
Nonoversampling Filter Disable Sequence
5.6 CS4399 Analog Output and Filtering
The CS4399 requires an external opamp filter stage for driving headphone loads. One of the typical filter topologies used
for this purpose is the multiple-feedback filter configuration. The CS4399 does not include phase or amplitude
compensation for an external filter. Therefore, the DAC system and phase response is dependent on the external circuitry.
5.7 Audio Output Power Down Sequences
Examples of power down sequences for PCM and DSD are shown in
and
, respectively. Follow the stated
sequence every time to shut down the audio output. The sequence assumes that the PDN_DONE_INT interrupt bit is
unmasked.
T
ASK
R
EGISTER
/B
IT
F
IELDS
V
ALUE
D
ESCRIPTION
Configure PCM filter
0x10010
0x99
0xC0001
0x0C
PCM Filter Option 0x90000
0x22
FILTER_SLOW_FASTB
PHCOMP_LOWLATB
NOS
Reserved
HIGH_PASS
DEEMP_ON
0
0
1
0 00
1
0
Nonoversampling filter is selected
High-pass filter is selected
0x10010
0x0
T
ASK
R
EGISTER
/B
IT
F
IELDS
V
ALUE
D
ESCRIPTION
Configure PCM filter
0x10010
0x99
0xC0001
0x0D
PCM Filter Option 0x90000
0x02
FILTER_SLOW_FASTB
PHCOMP_LOWLATB
NOS
Reserved
HIGH_PASS
DEEMP_ON
0
0
0
0 00
1
0
High-pass filter is selected
0x10010
0x0