Production Data
WM8352
14.5 CUSTOM MODES
The WM8352 provides three custom start-up modes. These are selected by setting the CONF1 and
CONF0 pins = 01, 10 or 11. The custom mode start-up sequences define the following parameters:
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Polarity of the ON pin (Active low or high)
Configuration of the USB power source
Configuration of the Watchdog timer mode
Configuration of the Control Interface mode
Configuration of the 32kHz oscillator (enabled or disabled)
Configuration of the real-time-clock (enabled or disabled)
Configuration of LDO1
Selection of crystal oscillator detect mode (see Section 14.3.6)
Configuration of the voltage settings and start-up timeslots for DC-DC and LDO supplies
Configuration of GPIO pins
In Development Mode, the RECONFIG_AT_ON register bit (see Section 14.4.2) may be used to
control the device configuration behaviour. In Custom Modes 01, 10 or 11, the default setting
(RECONFIG_AT_ON = 1) must always be used. Setting this bit to 0 may result in erroneous
behaviour and deviation from the custom configuration settings.
The custom modes do not allow configuring the WM8352 in the OFF state. As a result, evaluation
and debugging in custom modes is limited.
14.5.1 CONFIGURATION MODE 01
In Configuration Mode 01, the following general default settings apply:
PARAMETER
REGISTER SETTING
ON_POL = 1
DESCRIPTION
ON pin is Active Low
ON polarity
USB power source USB_SLV_500MA = 1
Selects 500mA limit in USB slave
Watchdog is disabled
Watchdog timer
Control Interface
WDOG_MODE [1:0] = 00
SPI_3WIRE = 0
Control Interface is 2-wire mode
SPI_4WIRE = 0
SPI_CFG = 0
32kHz oscillator
Real Time Clock
OSC32K_ENA = 1
RTC_TICK_ENA = 1
RTC_CLKSRC = 0
LDO1_PIN_MODE = 0
LDO1_PIN_EN = 0
32kHz Oscillator is enabled
Real Time Clock is enabled
LDO1
LDO1 controlled as normal via
register bits
Crystal detect
mode
Crystal detect mode is not enabled.
The default voltages and the power-up sequence for all DC-DCs and LDOs in Configuration Mode 01
are shown below in Table 65 and Figure 66.
The time delay between each time slot is approximately 1.28ms.
Note that the Limit Switch is not enabled automatically in Configuration Mode 01; as a result, the
Limit Switch remains open when the WM8352 enters the ACTIVE state.
PD, February 2011, Rev 4.4
117
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
