Rainbow Electronics ATmega128RFA1 - Manual (Page 128)

128
8266A-MCU Wireless-12/09
ATmega128RFA1
Table 9-67 MAX_CSMA_RETRIES Register Bits
Register Bits Value Description
0x0 No repetition of CSMA-CA procedure
0x1 One repetition of CSMA-CA procedure
0x2 ...
0x5 Five repetitions (highest IEEE 802.15.4
compliant value)
0x6 Reserved
MAX_CSMA_RETRIES2:0
0x7 Immediate frame re-transmission without
performing CSMA-CA
• Bit 0 – SLOTTED_OPERATION - Set Slotted Acknowledgment
When using RX_AACK mode in networks operating in beacon or slotted mode
according
to IEEE 802.15.4-2006, chapter 5.5.1 the register bit
SLOTTED_OPERATION indicates that acknowledgment frames are to be sent on back-
off slot boundaries (slotted acknowledgment). If this register bit is set the
acknowledgment frame transmission has to be initiated by the application software
using bit SLPTR of register TRXPR. This waiting state is signaled in sub register
TRAC_STATUS of register TRX_STATE with value SUCCESS_WAIT_FOR_ACK.
Table 9-68 SLOTTED_OPERATION Register Bits
Register Bits Value Description
0 The radio transceiver operates in unslotted
mode. An acknowledgment frame is
automatically sent if requested. SLOTTED_OPERATION
1 The transmission of an acknowledgment
frame has to be controlled by the
microcontroller.
9.12.45 CSMA_SEED_0 – Transceiver CSMA-CA Random Number Generator Seed Register
Bit 7 6 5 4 3 2 1 0
NA ($16D) CSMA_SEED_07:00 CSMA_SEED_0
Read/Write RW RW RW RW RW RW RW RW
Initial Value 1 1 1 0 1 0 1 0
This register contains the lower 8 bits of the CSMA_SEED. The upper 3 bits are part of
register CSMA_SEED_1. CSMA_SEED is the seed for the random number generation
that determines the length of the back-off period in the CSMA-CA algorithm. It is
recommended to initialize registers CSMA_SEED by random values. This can be done
using the bits RND_VALUE of register PHY_RSSI.
• Bit 7:0 – CSMA_SEED_07:00 - Seed Value for CSMA Random Number
Generator
These bits contain the bits [7:0] of the CSMA_SEED.