WM8325 Datasheet, PDF (111/254 Pages) Wolfson Microelectronics plc – Processor Power Management Subsystem

Production Data
WM8325
GPn_FN
Ah
Bh
Ch
Dh
Eh
Fh
GPIO OUTPUT
FUNCTION
External Power
Enable 1
External Power
Enable 2
System Supply
Good (PVDD
Good)
Converter Power
Good
(PWR_GOOD)
External Power
Clock
Auxiliary Reset
DESCRIPTION
Logic output assigned to one of the timeslots in the ON/OFF
and SLEEP/WAKE sequences. This can be used for sequenced
control of external circuits. See Section 15.3.
Logic output assigned to one of the timeslots in the ON/OFF
and SLEEP/WAKE sequences. This can be used for sequenced
control of external circuits. See Section 15.3.
Logic output from PVDD monitoring circuit. This function
represents the internal SYSOK signal. See Section 24.4.
Status output indicating that all selected DC-DC converters and
LDO regulators are operating correctly. Only asserted in ON
and SLEEP modes. See Section 15.13.
2MHz clock output suitable for clocking external DC-DC
converters. This clock signal is synchronized with the WM8325
DC Converters clocking signal. See Section 13.
This clock output is only enabled when either of the External
Power Enable signals (EPE1 or EPE2) is asserted. These
signals can be assigned to one of the timeslots in the ON/OFF
and SLEEP/WAKE sequences. See Section 15.3.
Logic output indicating a Reset condition. This signal is
asserted in the OFF state. The status in SLEEP mode is
configurable. See Section 11.7.
Note that the default polarity for this function (GPn_POL=1) is
“Active High”. Setting GPn_POL=0 will select “Active Low”
function.
Table 53 List of GPIO Output Functions
21.3 CONFIGURING GPIO PINS
The GPIO pins are configured using the Resister fields defined in Table 54.
The function of each GPIO is selected using the GPn_FN register field. The pin direction field
GPn_DIR selects between input functions and output functions. See Section 21.2 for a summary of
the available GPIO functions.
The polarity of each GPIO can be configured using the GPn_POL bits. This inversion is effective both
on GPIO inputs and outputs. When GPn_POL = 1, the non-inverted ‘Active High’ polarity applies. The
opposite logic can be selected by setting GPn_POL = 0.
The voltage power domain of each GPIO is determined by the GPn_PWR_DOM register. Note that
the available options vary between different GPIO pins, as described in Table 56.
A GPIO output may be either CMOS driven or Open Drain. This is selected using the GPn_OD bits.
Internal pull-up or pull-down resistors can be enabled on each pin using the GPn_PULL field. Both
resistors are available for use when the associated GPIO is an input. When the GPIO pin is
configured as an Open Drain output, the internal pull-up resistor may be required if no external pull-up
resistors are present.
A GPIO pin may be tri-stated using the GPn_ENA register field. When GPn_ENA = 0, the respective
pin is tri-stated. A tri-stated pin exhibits high impedance to any external circuit and is disconnected
from the internal GPIO circuits. The pull-up and pull-down resistors are disabled when a GPIO pin is
tri-stated.
GPIO pins can generate an interrupt (see Section 21.4). The GPn_INT_MODE field selects whether
the interrupt occurs on a single active edge only, or else on both rising and falling edges. When single
edge is selected, the active edge is the rising edge (when GPn_POL = 1) or the falling edge (when
GPn_POL = 0).
When GPIO10, GPIO11 or GPIO12 is used as an input to the AUXADC (see Section 18), it is
recommended that the respective GPIO(s) are tri-stated (ie. GPn_ENA = 0). The normal GPIO
functionality cannot be supported on a GPIO pin that is enabled as an input to the AUXADC.
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PD, February 2012, Rev 4.0
111