System Headphone Parasitic Resistances - Cirrus Logic CS42L42 Manual

5. Set LATCH_TO_VP
6. Set HSBIAS_CTRL
7. Set ADPTPWR = 100 (see
8. Set the analog soft-ramp rate
9. Set the digital soft-ramp rate (DSR_RATE; see
10.After load detection completes, ASR_RATE, DSR_RATE, ADPTPWR, and DAC_HPF_EN must be restored to
their previous values. See
See the detailed detection instruction sequence in
After an HP-detect event, if
capacitance of the output load. A 24-kHz tone is output on HPOUTA, and HS3 or HS4 (depending on China headset detect
results) is measured using an internal resistor bank as a reference.
RLA_STAT (see p. 148) reports resistance-detection results for Channel A as follows:
00: 15 
•
01: 30 
•
• 10: 3 k
• 11: Reserved
If the typical output resistance of less than ~300 is indicated, a low-capacitance load is assumed. If the resistance is
greater than 300  capacitance detection proceeds. After the detection sequence completes,
148) is set. The results of capacitor detection is reported in
p.
the value in HPOUT_LOAD(see
Notes:
• The HP path must be powered down before updating the HPOUT_LOAD setting and repowered afterwards.
• Low capacitance results were determined with C
4.4.5 Slow Start Control
Mixer, DAC, and HP soft ramping is enabled through
to DAC/HP volumes are applied slowly by stepping through each volume-control setting with a delay between steps equal
to an integer number of Fs periods. The delay between steps, which can vary from 1/Fs to 72/Fs periods, is set via
RATE and ASR_RATE (see
If ramping is disabled, changes occur immediately with the clock edge.

4.5 System Headphone Parasitic Resistances

Parasitic resistances limit the measurements on several specs, including the following:
• Headphone-to-analog input isolation
• Headphone interchannel isolation
• Headphone mute attenuation
• Headphone DC offset
DS1083F2
(see p. 150).
to 00 (Hi-Z Mode; see p. 150).
p. 155).
(ASR_RATE = 0111; see
Section 4.6 for details.
Ex. 5-5
HP_LD_EN is set (see p.
154), which determines the compensation of the headphone amplifier.
p.
p. 129).
4.5 System Headphone Parasitic Resistances
p. 129).
p. 129) = 0001.
for details.
148), the CS42L42 proceeds to detect the resistance and
CLA_STAT (see p.
= 1 nF; high capacitance results were determined with C
L
SLOW_START_EN (p. 129). If SLOW_START_EN = 111, changes
HPLOAD_DET_DONE
148). This result can be used to program
CS42L42
(see
= 10 nF.
L
DSR_
39