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Configuring Low-Power Sleep Mode

Popoto has two low-power sleep modes:

  • In POWERDOWN mode, nearly all board voltage supplies are shut down, resulting in very low-power sleep. It takes about 20 seconds to power up and exit POWERDOWN mode.
  • In DEEPSLEEP mode, the processor is placed into hibernation while RAM remains powered and refreshed. This mode consumes more power than POWERDOWN, but wakes in less than 1 second.

Each mode can be entered through an API or pshell command. pshell exposes the powerdown and deepsleep commands. Refer to the Popoto API reference for API access details.

Waking up a Modem​

In either low-power mode, a dedicated wake-up processor monitors acoustic signals in the water for a wake-up signal. The wake-up signal is based on the standard modem message header acquisition pattern. To wake a modem, send any message into the water. The acquisition signal wakes the modem, although the transmitted message itself is lost.