ATmega1284PR231 Atmel Corporation, ATmega1284PR231 Datasheet - Page 95

no-image

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
8.5.3
8.5.4
8.5.5
8111C–MCU Wireless–09/09
Data Interpretation
Interrupt Handling
Measurement Time
The current channel status (CCA_STATUS) and the CCA completion status (CCA_DONE) are
accessible in register 0x01 (TRX_STATUS). Note, register bits CCA_DONE and CCA_STATUS
are cleared in response to a CCA_REQUEST.
The completion of a measurement cycle is indicated by CCA_DONE = 1. If the radio transceiver
detected no signal (idle channel) during the measurement cycle, the CCA_STATUS bit is set to
1.
When using the "ene rg y above th re shold" algorith m, any received power abov e
CCA_ED_THRES level is interpreted as a busy channel. The "carrier sense" algorithm reports a
busy channel when detecting an IEEE 802.15.4 signal above the RSSI_BASE_VAL (see param-
eter 12.7.16). The radio transceiver is also able to detect signals below this value, but the
detection probability decreases with the signal power. It is almost zero at the radio transceivers
sensitivity level (see parameter 12.7.1).
Interrupt IRQ_4 (CCA_ED_DONE) is issued at the end of a manually initiated CCA
measurement.
Notes
The response time for a manually initiated CCA measurement depends on the receiver state.
In RX_ON state the CCA measurement is done over eight symbol periods and the result is
accessible 140 µs after the request (see above).
In BUSY_RX state the CCA measurement duration depends on the CCA Mode and the CCA
request relative to the reception of an SHR. The end of the CCA measurement is indicated by an
IRQ_4 (CCA_ED_DONE). The variation of a CCA measurement period in BUSY_RX state is
described in
Table 8-9.
CCA Mode
• A CCA request should only be initiated in Basic Operating Mode receive states. Otherwise
• Requesting a CCA measurement in BUSY_RX state and during an ED measurement, an
the radio transceiver generates an IRQ_4 (CCA_ED_DONE) and sets the register bit
CCA_DONE = 1, even though no CCA measurement was performed.
IRQ_4 (CCA_ED_DONE) could be issued immediately after the request. If in this case
register bit CCA_DONE = 0, an additional interrupt CCA_ED_DONE is issued after finishing
the CCA measurement and register bit CCA_DONE is set to 1.
1
2
Table 8-9 on page
CCA Measurement Period and Access in BUSY_RX state
Energy above threshold.
CCA result is available after finishing
automated ED measurement period.
Carrier sense only.
CCA result is immediately available after request.
Request within ED measurement
95.
(1)
Request after ED measurement
CCA result is immediately available after
request.
AT86RF231
95

Related parts for ATmega1284PR231