User Manual

96
8111A–AVR–05/08
AT86RF231
Note: 1. After receiving the SHR an automated ED measurement is started with a length of 8 symbol
periods (PSDU rate 250 kb/s), refer to Section 8.4 “Energy Detection (ED)” on page 91. This
automated ED measurement must be finished to provide a result for the CCA measurement.
Only one automated ED measurement per frame is performed.
It is recommended to perform CCA measurements in RX_ON state only. To avoid switching
accidentally to BUSY_RX state the SHR detection can be disabled by setting register bit
RX_PDT_DIS (register 0x15, RX_SYN), refer to Section 9.1 “Receiver (RX)” on page 101. The
receiver remains in RX_ON state to perform a CCA measurement until the register bit
RX_PDT_DIS is set back to continue the frame reception. In this case the CCA measurement
duration is 8 symbol periods.
3 Carrier sense with Energy above threshold (AND).
CCA result is available after finishing
automated ED measurement period.
CCA result is immediately available after
request.
0 Carrier sense with Energy above threshold (OR).
CCA result is available after finishing
automated ED measurement period
CCA result is immediately available after
request.
Table 8-9. CCA Measurement Period and Access in BUSY_RX state