Rainbow Electronics AT86RF231 - Manual (Page 139)

139
8111A–AVR–05/08
AT86RF231
Figure 11-8 on page 139 illustrates the packet structure of a High Data Rate Frame Buffer read
access.
Figure 11-8. Packet Structure - High Data Rate Frame Buffer Read Access
11.3.4 High Data Rate Energy Detection
According to IEEE 802.15.4 the ED measurement duration is 8 symbol periods. For frames
operated at higher data rates the automated ED measurement duration is reduced to 32 µs to
take the reduced frame length into account, refer to
Section 8.4 “Energy Detection (ED)” on
page 91 .
During Frame Buffer read access the ED value is appended to the PSDU data, refer to Section
11.3.3 “High Data Rate Frame Buffer Access” on page 138 .
11.3.5 High Data Rate Mode Options
Receiver Sensitivity Control
The different data rates between PPDU header (SHR and PHR) and PHY payload (PSDU)
cause a different sensitivity between header and payload. This can be adjusted by defining sen-
sitivity threshold levels of the receiver. With a sensitivity threshold level set (register bits
RX_PDT_LEVEL > 0), the receiver does not receive frames with an RSSI level below that
t h r e s h o l d . U n d e r t h e s e o p e r a t i n g c o n d i t i o n s t h e r e c e i v e r c u r r e n t c o n s u m p t i o n i s
reduced by 500 µA, refer to
Section 12.8 “Current Consumption Specifications” on page 161
parameter 12.8.3.
A description of the settings to control the sensitivity threshold with register 0x15 (RX_SYN) can
be found in
Section 9.1.4 “Register Description” on page 103 .
Reduced Acknowledgment Timing
On higher data rates the IEEE 802.15.4 compliant acknowledgment frame response time of
192 µs significantly reduces the effective data rate of the network. To minimize this influence in
Extended Operating Mode RX_AACK, refer to
Section 7.2.3 “RX_AACK_ON - Receive with
Automatic ACK” on page 51 , the acknowledgment frame response time can be reduced to
32 µs. Figure 11-9 on page 140 illustrates an example for a reception and acknowledgement of
a frame with a data rate of 2000 kb/s and a PSDU length of 80 symbols. The PSDU length of the
acknowledgment frame is 5 octets according to IEEE 802.15.4.
0 reserved[5:0] 0 MOSI
PHY_STATUS MISO
byte 1 (command byte)
1 XX
PHR[7:0]
byte 2 (data byte)
XX
PSDU[7:0]
byte 3 (data byte)
XX
PSDU[7:0]
byte n-1 (data byte)
XX
ED[7:0]
byte n (data byte)