ATmega1284PR231 Atmel Corporation, ATmega1284PR231 Datasheet - Page 142

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ATmega1284PR231

Manufacturer Part Number
ATmega1284PR231
Description
Manufacturer
Atmel Corporation
Datasheets

Specifications of ATmega1284PR231

Flash (kbytes)
128 Kbytes
Max. Operating Frequency
20 MHz
Max I/o Pins
32
Spi
3
Twi (i2c)
1
Uart
2
Adc Channels
8
Adc Resolution (bits)
10
Adc Speed (ksps)
15
Analog Comparators
1
Crypto Engine
AES
Sram (kbytes)
16
Eeprom (bytes)
4096
Operating Voltage (vcc)
1.8 to 3.6
Timers
3
Frequency Band
2.4 GHz
Max Data Rate (mb/s)
2
Antenna Diversity
Yes
External Pa Control
Yes
Power Output (dbm)
3
Receiver Sensitivity (dbm)
-101
Receive Current Consumption (ma)
13.2
Transmit Current Consumption (ma)
14.4
Link Budget (dbm)
104
11.4
11.4.1
11.4.2
8111C–MCU Wireless–09/09
Antenna Diversity
Overview
Antenna Diversity Application Example
The Antenna Diversity implementation is characterized by:
Due to multipath propagation effects between network nodes, the receive signal strength may
vary and affect the link quality, even for small changes of the antenna location. These fading
effects can result in an increased error floor or loss of the connection between devices.
To improve the reliability of an RF connection between network nodes Antenna Diversity can be
applied to reduce effects of multipath propagation and fading. Antenna Diversity uses two anten-
nas to select the most reliable RF signal path. This is done by the radio transceiver during
preamble field search without the need for microcontroller interaction. To ensure highly indepen-
dent receive signals on both antennas, the antennas should be carefully separated from each
other.
If a preamble field is detected on one antenna, this antenna is selected for reception. Otherwise
the search is continued on the other antenna and vice versa.
Antenna Diversity can be used in Basic and Extended Operating Modes and can also be com-
bined with other features and operating modes like High Data Rate Mode and RX/TX Indication.
A block diagram for an application using an antenna switch is shown in
142.
Figure 11-10. Antenna Diversity - Block Diagram
• Improves signal path robustness between nodes
• AT86RF231 self-contained antenna diversity algorithm
• Direct register based antenna selection
ANT0
ANT1
SW1
B1
1
2
3
4
5
6
AVSS
DIG4
RFP
RFN
AVSS
...
DIG3
9
AT86RF231
10
Figure 11-10 on page
AT86RF231
142

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