Wavecard-Waveport User Manual
Coronis Systems
3.2 Wake-up and synchronization
Wavecard optimizes power consumption by using STANDBY mode, waking up periodically to poll for radio
activity. The wake-up period is defined by the value of the
AWAKENING_PERIOD
parameter, expressed in
multiples of 100 ms (1 second by default).
3.2.1 Transmitting and receiving frames
When transmitting a frame to a remote module, the transmitter begins an awakening procedure called
WakeUp
, which is used to wake receiving modules, which then switch to RF reception mode. A succession of
binary symbols are sent by the radio during this preamble procedure.
There are two types of wake-up procedures:
Long wake-up
Used when transmitting a request towards a remote module. You may set
duration parameters (1100 ms by default), which is generally equal to the
wake-up period of the module you are trying to reach,
plus
100 ms in order
to avoid transmitting between two reception periods.
Short wake-up
Used only when responding to a point-to-point request. Duration is 50ms and
cannot be changed.
NUM
DESCRIPTION
VALUE
SIZE
(in bytes)
0x00
AWAKENING_PERIOD
RF polling period in multiples of 100 ms
Period in multiples of 100 ms
(by default, 0x0A for one second)
0 = nearly constant reception (every 20 ms)
1
0x01
WAKEUP_TYPE
Type of wake-up used during frame transmission
0: long wake-up (default setting)
1: short wake-up = 50 ms
1
0x02
WAKEUP_LENGTH
Duration of the Wake up when long wake up is set up.
This value must be higher than the RF polling period.
Value in multiples of 1ms, LSB defined first.
Default value : 1100 ms
Min. value = 20 ms (0x1400)
Max. value = 10 sec. (0x1027)
2
When the receiving RF module detects the wake-up procedure, it executes the following operations:
•
It starts a time-out to wait for the synchronization word (sync). Duration of the time-out is slightly
longer than its WakeUp period, and cannot be changed.
•
It begins a phase of validating the WakeUp preamble (WakeUp detection). This phase
corresponds to the detection of several successive symbols that compose the preamble. If
detection fails, the module returns to stand-by mode. Detection time depends on transmission
speed.
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