WM8321 datasheet(116/253 Pages) WOLFSON

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WM8321

Production Data

PD, February 2012, Rev 4.0

116

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

DRIVE MODE

LED ‘ON’

TIME

ON:OFF

DUTY CYCLE

LED1 or

LED2

Power Sequence Failure

Pulsed sequence

(4 pulses)

1:1

PVDD Low

Continuous

pulsed

250ms

1:3

ON state

Constant

n/a

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

BIT

LABEL

DEFAULT

DESCRIPTION

R16460

(404Ch)

Status LED1

9:8

LED1_MODE

[1:0]

LED1 Mode

(Controls LED1 in Manual Mode

only.)

00 = Off

01 = Constant

10 = Continuous Pulsed

11 = Pulsed Sequence

5:4

LED1_SEQ_LE

N [1:0]

LED1 Pulse Sequence Length

(when LED1_MODE = Pulsed

Sequence)

00 = 1 pulse

01 = 2 pulses

10 = 4 pulses

11 = 7 pulses

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