Chipcon CC400DB, Руководство пользователя

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SWRU068
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2.2 Demonstrator operation
The CC400DB demonstrates a very simple two-way remote control system.
To “wake” the module from power-down mode, simply press the “ON” button for a
short time. The LED will then start blinking with a period of approximately 1 second.
This is the “heart-beat” that shows the module is operating. During the short time the
LED is lit, the module is in active receive mode, and listens for a data packet. If a data
packet is not found, it goes to a “rest” mode for approximately 1 second. Hence, the
module listens for a data packet every second. This polled receiver algorithm is
implemented in order to save battery power.
Both modules should be awaked before a successful transmission can take place. A
transmission is initiated by pushing the “TX” button. A data packet of approximately 1.5
second duration is then transmitted. The data packet consists of a long preamble and a
short data field. The pre-amble is longer than 1 second to ensure that the transmission
intercepts with the polled receiver.
The data packet transmitted consists of a blinking sequence of approximately 2 seconds
duration, and will be shown on the receiver’s LED if the data packet was received free
of errors. The same “message” with an acknowledgement flag is then returned from the
receiver to the initial transmitter. Again, the blinking sequence will be shown on the
LED as a receipt acknowledge.
The modules will enter sleep mode after being left without operation for about one
minute. The CC400 and the micro-controller are then in power-down mode, ensuring
minimum power consumption.
The timing diagram below illustrates a packet transmission sequence when the
transmission is initiated from device number 2.
2.3 System parameters
The system parameters used to generate the configuration data for the CC400DB is
shown below. This is a printout from the SmartRF® Studio software.
System parameters:
X-tal frequency: 12.000000 MHz
X-tal accuracy: +/- 50 ppm
DEVICE 1
DEVICE 2
Receiver polling
Devices are active for one
minute until time-out
Initial
trans-
mission
Message
shown on
receiver LED
LED (ACK)
RX LED TX ACK
TX RX
Ack.
trans-
mission
Acknowledge
shown on
receiver LED
Sleep
mode