14.8.38 CSMA_SEED_1
The CSMA_SEED_1 register is a control register for RX_AACK and contains a part of the CSMA_SEED for the CSMACA algorithm.
| Name: | CSMA_SEED_1 |
| Offset: | 0x2E |
| Reset: | 0x42 |
| Property: | - |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| AACK_FVN_MODE[1:0] | AACK_SET_PD | AACK_DIS_ACK | AACK_I_AM_COORD | CSMA_SEED_1[2:0] | |||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | |
Bits 7:6 – AACK_FVN_MODE[1:0] AACK_FVN_MODE
The register bits AACK_FVN_MODE control the ACK behavior dependent on FCF frame version number within RX_AACK mode.
| Value | Description |
|---|---|
| 0x0 | Accept frames with version number 0 |
| 0x1 | Accept frames with version number 0 or 1 |
| 0x2 | Accept frames with version number 0 or 1 or 2 |
| 0x3 | Accept frames independent of frame version number |
- AACK_FVN_MODE value one indicates frames according to [2] IEEE 802.15.4–2006, a value of three indicates frames according to [1] IEEE 802.15.4–2003 standard.
The frame control field of the MAC header (MHR) contains a frame version subfield. The setting of register bits AACK_FVN_MODE specifies the frame filtering behavior of the AT86RF212B. According to the content of these register bits the radio transceiver passes frames with a specific frame version number, number group, or independent of the frame version number.
Thus the register bits AACK_FVN_MODE defines the maximum acceptable frame version. Received frames with a higher frame version number than configured do not pass the frame filter and are not acknowledged.
The frame version field of the acknowledgment frame is set to zero according to [2] IEEE 802.15.4-2006, Section 7.2.2.3.1 Acknowledgment frame MHR fields.
Bit 5 – AACK_SET_PD AACK_SET_PD
The content of AACK_SET_PD bit is copied into the frame pending subfield of the acknowledgment frame if the ACK is the response to a data request MAC command frame.
| Value | Description |
|---|---|
| 0x0 | Pending data bit set to zero |
| 0x1 | Pending data bit set to one |
In addition, if register bits AACK_FVN_MODE (register 0x2E, CSMA_SEED_1) are configured to accept frames with a frame version other than zero or one, the content of register bit AACK_SET_PD is also copied into the frame pending subfield of the acknowledgment frame for any MAC command frame with a frame version of two or three that have the security enabled subfield set to one. This is done with the assumption that a future version of the [2] IEEE 802.15.4-2006 standard might change the length or structure of the auxiliary security header.
Bit 4 – AACK_DIS_ACK AACK_DIS_ACK
If this bit is set no acknowledgment frames are transmitted in RX_AACK Extended Operating Mode, even if requested.
| Value | Description |
|---|---|
| 0x0 | Acknowledgment frames are transmitted |
| 0x1 | Acknowledgment frames are not transmitted |
Bit 3 – AACK_I_AM_COORD AACK_I_AM_COORD
This register bit has to be set if the node is a PAN coordinator. It is used for frame filtering in RX_AACK.
| Value | Description |
|---|---|
| 0x0 | PAN coordinator addressing is disabled |
| 0x1 | PAN coordinator addressing is enabled |
If AACK_I_AM_COORD = 1 and if only source addressing fields are included in a data or MAC command frame, the frame shall be accepted only if the device is the PAN coordinator and the source PAN identifier matches mac- PANId, for details refer to [2] IEEE 802.15.4-2006, Section 7.5.6.2 (third-level filter rule six).
Bits 2:0 – CSMA_SEED_1[2:0] CSMA_SEED_1
Higher 3-bit of CSMA_SEED, bits [10:8]. Seed for random number generation in the CSMA-CA algorithm.
| Value | Description |
|---|---|
| 0x2 | These register bits are the higher 3-bit of the CSMA_SEED, bits [10:8]. The lower part is in register 0x2D (CSMA_SEED_0), see register CSMA_SEED_0 for details. |