Rainbow Electronics ATmega128RFA1 - Manual (Page 127)

127
8266A-MCU Wireless-12/09
ATmega128RFA1
• Bit 7:0 – IEEE_ADDR_77:70 - MAC IEEE Address
These bits map to the bits [63:56] of the 64 bit MAC IEEE address.
9.12.44 XAH_CTRL_0 – Transceiver Extended Operating Mode Control Register
Bit 7 6
NA ($16C) MAX_FRAME_RETRIES3 MAX_FRAME_RETRIES2 XAH_CTRL_0
Read/Write RW RW
Initial Value 0 0
Bit 5 4
NA ($16C) MAX_FRAME_RETRIES1 MAX_FRAME_RETRIES0 XAH_CTRL_0
Read/Write RW RW
Initial Value 1 1
Bit 3 2
NA ($16C) MAX_CSMA_RETRIES2 MAX_CSMA_RETRIES1 XAH_CTRL_0
Read/Write RW RW
Initial Value 1 0
Bit 1 0
NA ($16C) MAX_CSMA_RETRIES0 SLOTTED_OPERATION XAH_CTRL_0
Read/Write RW RW
Initial Value 0 0
This register is used to control various settings of the Extended Operating Mode.
• Bit 7:4 – MAX_FRAME_RETRIES3:0 - Maximum Number of Frame Re-
transmission Attempts
The setting of MAX_FRAME_RETRIES in TX_ARET mode specifies the number of
attempts to retransmit a frame when it was not acknowledged by the recipient. The
transaction gets canceled if the number of attempts exceeds MAX_FRAME_RETRIES.
Table 9-66 MAX_FRAME_RETRIES Register Bits
Register Bits Value Description
0x0 Retransmission of frame is not attempted.
0x1 Retransmission of frame is attempted once.
0x2 ...
MAX_FRAME_RETRIES3:0
0xF Retransmission of frame is attempted 15
times.
• Bit 3:1 – MAX_CSMA_RETRIES2:0 - Maximum Number of CSMA-CA Procedure
Repetition Attempts
MAX_CSMA_RETRIES specifies the number of retries in TX_ARET mode to repeat the
CSMA-CA procedure before the transaction gets canceled. According to IEEE 802.15.4
the valid range of MAX_CSMA_RETRIES is 0 to 5. A value of MAX_CSMA_RETRIES =
7 initiates an immediate frame transmission without performing CSMA-CA. This may
especially be required for slotted acknowledgment operation. MAX_CSMA_RETRIES =
6 is reserved.