ATMEGA128RFA1-ZU Atmel, ATMEGA128RFA1-ZU Datasheet - Page 73

• Manufacturer Part Number: ATMEGA128RFA1-ZU
• Description: IC AVR MCU 2.4GHZ XCEIVER 64QFN
• Manufacturer: Atmel
• Series: ATMEGAr

Specifications of ATMEGA128RFA1-ZU

• Frequency: 2.4GHz
• Data Rate - Maximum: 2Mbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Applications: General Purpose
• Power - Output: 3.5dBm
• Sensitivity: -100dBm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Current - Receiving: 12.5mA
• Current - Transmitting: 14.5mA
• Data Interface: PCB, Surface Mount
• Memory Size: 128kB Flash, 4kB EEPROM, 16kB RAM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN, Exposed Pad
• Rf Ic Case Style: QFN
• No. Of Pins: 64
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Processor Series: ATMEGA128x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 16 KB
• Interface Type: JTAG
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 38
• Number Of Timers: 6
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVR128RFA1-EK1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.5.6.2 Request a LQI Measurement
9.5.6.3 Data Interpretation
8266A-MCU Wireless-12/09
can be associated with an expected packet error rate. The PER is the ratio of erroneous
received frames to the total number of received frames. A PER of zero indicates no
frame error whereas at a PER of one no frame was received correctly.
The radio transceiver uses correlation results of multiple symbols within a frame to
determine the LQI value. This is done for each received frame. The minimum frame
length for a valid LQI value is two octets PSDU. LQI values are integers ranging from 0
to 255.
The following figure shows an example of a conditional packet error rate when receiving
a certain LQI value.
Figure 9-19. Conditional Packet Error Rate versus LQI
The values are taken from received frames of PSDU length of 20 octets on
transmission channels with reasonable low multipath delay spreads. If the transmission
channel characteristic has a higher multipath delay spread than assumed in the
example, the PER is slightly higher for a certain LQI value. Since the packet error rate
is a statistical value, the PER shown in
of transactions. A reliable estimation of the packet error rate cannot be based on a
single or a small number of LQI values.
The LQI byte can be obtained after a frame has been received by the radio transceiver.
One additional byte is automatically attached to the received frame containing the LQI
value. This information can also be read via Frame Buffer read access, see
accessible Frame Content" on page
TRX24_RX_END interrupt.
According to IEEE 802.15.4 a low LQI value is associated with low signal strength
and/or high signal distortions. Signal distortions are mainly caused by interference
signals and/or multipath propagation. High LQI values indicate a sufficient high signal
power and low signal distortions.
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1
0
0
50
100
LQI
Figure 9-19 above
78. The LQI byte can be read after the
150
ATmega128RFA1
200
is based on a huge number
250
"User
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