ZHCSCB3D March 2014 – March 2018 PCM1860 , PCM1861 , PCM1862 , PCM1863 , PCM1864 , PCM1865
PRODUCTION DATA.
Energysense functionality has been added to the PCM186x 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, and the rest of the board (for example, amplifiers, and so on). The PCM186x 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 software-controlled devices. The PCM1860 and PCM1861 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.
| 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 register Set. | Host Wakes and services interrupt (reads register) | 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 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 to SLEEP mode. | MCU will need to mask that interrupt. |