ATmega644R212 Atmel Corporation, ATmega644R212 Datasheet - Page 138

• Manufacturer Part Number: ATmega644R212
• Manufacturer: Atmel Corporation

Specifications of ATmega644R212

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 20 MHz
• Max I/o Pins: 32
• Spi: 3
• Twi (i2c): 1
• Uart: 1
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Crypto Engine: AES
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Operating Voltage (vcc): 1.8 to 3.6
• Timers: 3
• Frequency Band: 700/800/900MHz
• Max Data Rate (mb/s): 1
• Antenna Diversity: No
• External Pa Control: Yes
• Power Output (dbm): 10
• Receiver Sensitivity (dbm): -110
• Receive Current Consumption (ma): 9.0
• Transmit Current Consumption (ma): 18 at 5dBm
• Link Budget (dbm): 120

Figure 11-6. High Data Rate Frame Structure
11.3.3
8111C–MCU Wireless–09/09
250 kb/s
500 kb/s
1000 kb/s
2000 kb/s
0
High Data Rate Frame Buffer Access
192
PSDU: 80 octets
PSDU: 80 octets
PSDU: 80 octets
PSDU: 80 octets
Due to the overhead caused by the SHR, PHR as well as the FCS, the effective data rate is
lower than the selected data rate. This is also affected by the length of the PSDU. A graphical
representation of the effective PSDU data rate is shown in
Figure 11-7. Effective Data Rate "B" for High Data Rate Mode
The effective throughput is further affected by the MAC overhead, the acknowledgment scheme
as well as the MCU processing capability. Consequently, High Data Rate transmission and
reception is useful for large PSDU lengths due to the higher effective data rate, or to reduce the
power consumption of the system. When using High Data Rate Modes the active on-air time is
significantly reduced.
The Frame Buffer access to read or write frames for High Data Rate transmission is similar to
the procedure described in
512
1600
1400
1200
1000
800
600
400
200
0
0
832
20
2000
1000
500
250
2000 kb/s
Section 6.2.2 “Frame Buffer Access Mode” on page
40
1000 kb/s
1472
PSDU length in octets
60
500 kb/s
80
Figure 11-7 on page
250 kb/s
100
AT86RF231
120
138.
20. However,
2752
time [µs]
138