WM8321
Production Data
22.2.2 POWER STATE STATUS
Setting LEDn_SRC = 01 configures the associated LED to indicate Power State status. Under this
selection, four different conditions may be indicated, as defined in Table 61.
LED DRIVER
DESCRIPTION
Power Sequence Failure
PVDD Low
DRIVE MODE
LED ‘ON’
TIME
ON:OFF
DUTY CYCLE
Pulsed sequence
(4 pulses)
1s
1:1
1:3
n/a
Continuous
pulsed
250ms
n/a
LED1 or
LED2
ON state
Constant
SLEEP state
Continuous
pulsed
250ms
1:7
Table 61 System Status LED Outputs - Power State Status
If more than one of the conditions listed occurs simultaneously, then the LED output pattern is
controlled by the condition in the highest position within the list above.
For example, if the PVDD Low condition occurs while in the ON or SLEEP states, then the LED
output follows the pattern defined for the PVDD Low condition.
The PVDD Low indication is asserted if PVDD is less than the user-selectable threshold
SYSLO_THR, as described in Section 24.4.
Note that, in the case of Power Sequence Failure, the transition to OFF occurs after the 4 LED pulses
have been emitted.
22.2.3 MANUAL MODE
Setting LEDn_SRC = 11 configures the associated LED to operate in Manual Mode, which is
configured using additional register fields.
In Manual Mode, the LED output can be commanded as Off, On (Constant), Continuous Pulsed or
Pulsed Sequence. The selected operation is determined by the LEDn_MODE registers as described
in Table 62.
In Continuous Pulsed mode and Pulsed Sequence mode, the ‘On’ time and the Duty Cycle can be
configured using the LEDn_DUR and LEDn_DUTY_CYC registers respectively.
In Pulsed Sequence mode, the number of pulses in the sequence can be selected using the
LEDn_SEQ_LEN register. On completion of the commanded number of pulses, the LED remains off
until LEDn_MODE or LEDn_SRC is changed to another value.
ADDRESS
R16460
(404Ch)
BIT
LABEL
DEFAULT
DESCRIPTION
LED1 Mode
LED1_MODE
[1:0]
9:8
00
(Controls LED1 in Manual Mode
only.)
Status LED1
00 = Off
01 = Constant
10 = Continuous Pulsed
11 = Pulsed Sequence
LED1 Pulse Sequence Length
LED1_SEQ_LE
N [1:0]
5:4
10
(when LED1_MODE = Pulsed
Sequence)
00 = 1 pulse
01 = 2 pulses
10 = 4 pulses
11 = 7 pulses
PD, February 2012, Rev 4.0
116
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
