Data Sheet

SIGNALS AND PINS
LOW POWER MODE
39 PROPRIETARY SP150Q DATASHEET
SEQUANS Communications
4.5 Low Power Mode
The SP150Q integrates several mechanisms to support power consumption
optimization during operation and during low-power mode.
SP150Q can be woken from low power mode through:
• USB resume signaling (when the host supports it)
• USB plug / unplug event (reported by the signal USB_EXT_VBUSVLD)
• SDIO interrupt on SDIO_HOST_D1
• Two dedicated input signal WAKE_0 and WAKE_1
Note: Wake from activity on the UARTx interfaces is not possible
directly. It can be achieved by connecting a SP150Q's GPIO
driven by the external device before resuming UARTx
activity.
In a use case where a device on the far end of a UART link needs
to wake SP150Q, that device must provide a signal to one of
SP150Q's WAKE_x signals.
If the end device has an output that says it is ready to transmit a
character over the UART, then that signal can be connected to one
of the SP150Q's WAKE_x signals. If not, then that device should
use a GPIO or other signal to stimulate SP150Q's WAKE_x signal.
WAKE_x signals are active only when the SP150Q is asleep.
To get the lowest possible power consumption during low-power mode, all
IOs must be stable. At software configuration time, take care of the following,
to prevent them from being in conflict or floating:
• Pads that are not driven by an external device shall be driven low by soft-
ware if they have a GPIO or GPO or RFDATA mode that allows it.
• For pads that are known to be driven by an external device:
Configure that external device to hold the signal stable during low-power
mode, and configure SP150Q to treat that pin as an input, without internal
pull-up or pull-down.
• For pads where, at the time of low-power mode, the signal may or may not
be driven by an external device:
Configure SP150Q to enable the internal pull-up/pull-down on the pad to
guarantee that it will not be floating during low-power mode.