PCM1860 datasheet(49/141 Pages) TI1

49 / 141 page

Time of loss of signal

(Y minutes )

INT

Threshold

Level

1 ms

Stopped BCK and LRCK by the Host

Sleep State

PCM1860-Q1, PCM1861-Q1, PCM1862-Q1

PCM1863-Q1, PCM1864-Q1, PCM1865-Q1

www.ti.com

SLASE64A – DECEMBER 2014 – REVISED JUNE 2017

Product Folder Links: PCM1860-Q1 PCM1861-Q1 PCM1862-Q1 PCM1863-Q1 PCM1864-Q1 PCM1865-Q1

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9.3.11 Energysense

Energysense functionality has been added to the PCM186x-Q1 to aid with auto-sleep and auto-wakeup for end

equipment systems that are expected to be sold within the European Union. The latest Ecodesign legislation in

Europe has demanded that products consume less than 500 mW in standby. Most off-the-shelf external power

adaptors can consume 300 mW when idling, leaving the system with only 200 mW available. In many systems

that require that almost everything be powered down in sleep mode after there is no more content to be played,

and then to be powered back up when signal enters the system again.

Energysense is designed to work in collaboration with a microcontroller to trigger interrupts notifying the

microcontroller to change the state of the PCM186x-Q1, and the rest of the board (for example, amplifiers, and

so on). The PCM186x-Q1 does not automatically switch between sleep and wake modes.

Energysense is split into two functions: signal loss flag and signal resume flag. Both are available on the

PCM186x-Q1 software-controlled devices. The PCM1860-Q1 and PCM1861-Q1 only support signal resume, as

shown in Table 17. By default, the signal resume threshold is set at –57 dBFS. Signal resume (autowakeup) only

functions when the device has been set to sleep.

Table 17. Energysense States

MODE

PURPOSE

CONDITIONS

POSITIVE OUTCOME

WORST CASE

SLEEP

(Signal Detect

Mode)

Detect Input Signal and Wake up

from SLEEP

BCK and LRCK stopped (not locked) or

Host Wakes and services interrupt (reads

Host Doesn't respond or start clocks.

Trigger Interrupt when input crosses

above (threshold)

Host Starts BCK/LRCK. (Moving system to

ACTIVE mode) or writes to register.

PCM186x-Q1 keeps triggering interrupts

until host responds.

Trigger for 1ms every X seconds until

clocks start (x=1 by default)

ACTIVE

(Signal Loss

Mode)

Detect content below (threshold)

over time

BCK and LRCK are currently running

System can choose to go to sleep or not. If

not, reset interrupt

If system does not sleep, remain in Mode

2, and prompt every Y.

Assist system to sleep after

audio inactivity (for example,

Source is off, but speaker still

on)

If no content above -(threshold) dB for Y

minutes, drive interrupt.

If System decides to sleep, stop BCK/LRCK.

This will move PCM186x-Q1 to SLEEP mode.

MCU will need to mask that interrupt.

9.3.11.1 Energysense Signal Loss Flag

The main ADC constantly monitors the input signal level while in ACTIVE mode. Should the input level remain

below a register defined threshold (for example –60 dB - Virtual Coefficient 0x2C, programmable through Page

1.) for a register defined amount of time (for example 1 minute - set by SIGDET_LOSS_TIME (Page.0, 0x33) ),

an interrupt can be generated.

If the system MCU decides to move to sleep mode, the PCM186x-Q1 can be moved to SLEEP by stopping

BCK/LRCK or using PWRDN_CTRL (Page.0, 0x70); see Table 17 for details.

If BCK and LRCK are stopped by the host after the interrupt, the device goes to the sleep state as shown in

Figure 37. Otherwise, the interrupt continues for a few seconds, defined by SIGDET_INT_INTVL (Page.0, 0x36)

unless the interrupt and timeout counter is reset.

Figure 37. Energysense Signal Loss

PCM1860 Datasheet(PDF) 49 Page - Texas Instruments

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