Cirrus Logic CS35L32 - Manual (Page 19)

DS963F4 19
CS35L32
4.8 Signal Monitoring
4.7.1 Error Conditions
Table 4-3 lists overtemperature error status and mask bits.
The overtemperature error and warning error conditions are described in detail in the following:
• Overtemperature warning (OTW). An OTW event occurs when the die temperature exceeds the overtemperature
threshold (listed in Table 3-3 ). When this occurs, an OTW (see p. 41 ) event is registered in the interrupt status
( Section 7.19 ); if M_OTW = 0, INT is asserted.
To exit the condition, the temperature must drop below the threshold and interrupt status 1 register must be read.
• Overtemperature error (OTE). An OTE event occurs when the die temperature exceeds the internally preset error
threshold (see Table 3-3 ). When this occurs, an OTE (see p. 41 ) event is registered in the interrupt status and, if
M_OTE = 0, INT is asserted. The CS35L32 shuts down, the Class D amplifier enters Speaker Safe Mode, as
described in Section 4.3.4 , and the LED drivers shut down.
To exit, the temperature must drop below the overtemperature shutdown threshold and OTE_RLS must be
sequenced as described in Section 7.15 . After OTE release, the amplifier and LED drivers recover to preshutdown
settings. The LED drivers must be retriggered with FLEN and/or FLINH inputs for a lighting event to occur.
4.8 Signal Monitoring
Signal-monitoring ADCs, shown in Fig. 4-5 , give upstream system processors access to important signals entering and
exiting the device. The three monitoring signals are as follows:
• VPMON: Monitors the voltage on the VP pin, which is most commonly the battery for the system.
• VMON: Monitors the output voltage of the Class D amplifier.
• IMON: Monitors the current that flows into the load being driven by the Class D amplifier.
An integrated ADC digitizes these analog signals, at which point, the audio/data serial port (ADSP) can send them to the
system processor.
Figure 4-5. Signal Monitoring Block Diagram (PDN_xMON = 0)
4.8.1 Power-Up and Power-Down Bits (PDN_xMON)
The three ADCs can be powered down independently via their respective PDN_xMON bit in the control port, see
Section 7.6 . To power down an ADC and its associated support circuitry, its PDN_xMON bit must be set; clearing PDN_
xMON powers up the corresponding circuitry.
Note: For proper operation, MCLK must be at the correct frequency ( MCLK_ERR = 0; see p. 41 ) and the device must
be powered ( PDN_ALL = 0; see p. 36 ).
Table 4-3. Die Temperature Monitoring Configuration
Error Cross-Reference to Register Field Description
Overtemperature error/Overtemperature error mask
Overtemperature warning/Overtemperature warning mask
Overtemperature error release
OTE p. 41/M_OTE p. 40
OTW p. 41/M_OTW p. 40
OTE_RLS p. 40
Signal Monitoring
VSENSE+
Multibit
 ADC
VSENSE–
ISENSE+
ISENSE–
Multibit
 ADC
To Audio/
Data Serial
port
VP (3.0–5.25 V)
Multibit
 ADC
Range Scaling
–30 to +36 dB
6-dB steps
VMON ADC Front End
LP
IMON ADC Front End
LP
IMON_SCALE on p. 38
(PDN_xMON = 0)