NRF9E5 Datasheet, PDF (28/104 Pages) List of Unclassifed Manufacturers – 433/868/915MHz RF Transceiver with Embedded 8051 Compatible Microcontroller and 4 Input, 10 Bit ADC

PRODUCT SPECIFICATION
nRF9 E5 Single Chip Transceiver with Embedded Microcontroller and ADC
9.8 Address Match
When the nRF905 is in ShockBurst ^TM RX mode, the Address Match (AM) pin is set
high as soon as an incoming package with an address that is identical with the device’s
own identity is received. With the Address Match pin the controller is alerted that the
nRF905 is receiving data actually before the Data Ready (DR) signal is set high. If the
Data Ready (DR) pin is not set high i.e. the CRC is incorrect then the Address Match
(AM) pin is reset to low at the end of the received data packet. This function can be very
useful for an MCU. If Address Match (AM) is high then the MCU can make a decision
to wait and see if Data Ready (DR) will be set high indicating a valid data package has
been received or ignore that a possible package is being received and switch modes.
9.9 Data Ready
The Data Ready (DR) signal makes it possible to largely reduce the complexity of the
MCU software program.
In ShockBurst ^TM TX, the Data Ready (DR) signal is set high when a complete package
is transmitted, telling the MCU that the nRF905 is ready for new actions. It is reset to
low at the start of a new package transmission or when switched to a different mode i.e.
receive mode or standby mode.
In ShockBurst ^TM TX Auto Retransmit the Data Ready (DR) signal is set high at the
beginning of the pre-amble and is set low at the end of the preamble. The Data Ready
(DR) signal therefore pulses at the beginning of each transmitted data packet.
In ShockBurst ^TM RX, the signal is set high when nRF905 has received a valid package,
i.e. a valid address, package length and correct CRC. The MCU can then retrieve the
payload via the SPI interface. The Data Ready (DR) pin is reset to low once the data has
been clocked out of the data buffer or the device is switched to transmit mode.
9.10 Auto Retransmit
One way to increase system reliability in a noisy environment or in a system without
collision control is to transmit a package several times. This is easily accomplished with
the Auto Retransmit feature in nRF905. By setting the AUTO_RETRAN bit to “1” in
the configuration register, the circuit keeps sending the same data package as long as
TRX_CE and TX_EN is high. As soon as TRX_CE is set low the device will finish
sending the packet it is currently transmitting and then return to standby mode.
9.11 RX Reduced Power Mode
To maximize battery lifetime in application where the nRF905 high sensitivity is not
necessary; nRF905 offers a built in reduced power mode. In this mode, the receive
current consumption reduces from 12.5mA to only 10.5mA. The sensitivity is reduced to
typical –85dBm, ±10dB. Some degradation of the nRF905 blocking performance should
be expected in this mode. The reduced power mode is an excellent option when using
Carrier Detect to sense if the wanted channel is available for outgoing data.
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway -Phone [phone] - Fax [phone]
Revision: 1.1
Page 28 of 104
June 2004