Texas Instruments SimpleLink CC2620 Technical Reference Manual page 1571

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with the BLE specification are considered valid. For an ADV_DIRECT_IND, valid means a length field of
12, and for ADV_IND messages it means a length field in the range 6–37. If
pParams ->initConfig.bStrictLenFilter is 0, all received packets with a length field less than or equal to the
maximum length of an advertiser packet (37, if not overridden) are considered valid. If the length is not
valid, the receiver is stopped.
PDU Type
ADV_IND
ADV_IND
ADV_IND
ADV_DIRECT_IND
ADV_DIRECT_IND
ADV_DIRECT_IND
ADV_DIRECT_IND
ADV*_IND with invalid length
Other
Table 23-128. Descriptions of the Actions to Take on Packets Received by Initiator
Action Number bCrcErr
1 0
2 0
3 1
4 —
If the packet received did not fit in the RX queue, the packet is received to the end, but the received bytes
are not stored. If the packet would normally not have been discarded from the RX buffer, the operation
ends.
If the action from the received packet is number 2, a CONNECT_REQ packet is transmitted. When
transmitting a CONNECT_REQ, the radio CPU constructs this packet. In the header, the PDU Type bits
are 0101b. The TXAdd bit is as shown in pParams ->initConfig.deviceAddrType. The RXAdd bit is as
shown in the TXAdd field of the header of the received ADV_IND or ADV_DIRECT_IND message. The
length is calculated from the length of the LLData, pParams->connectReqLen + 12. The RFU bits are 0.
The payload starts with the 6-byte device address, read from pParams ->pDeviceAddress, followed by the
6-byte peer address read from the AdvA field of the received message. The rest of the payload is read
from the pParams->pConnectData buffer. If pParams ->initConfig.bDynamicWinOffset is 1, the radio CPU
replaces the bytes in the WinSize and WinOffset position with a calculated value as explained below. After
a CONNECT_REQ message has been transmitted, the operation ends.
Two triggers to end the operation are set up by pParams->endTrigger/pParams->endTime and
pParams->timeoutTrigger/pParams->timeoutTime, respectively. If either of these triggers occurs, the radio
operation ends as soon as possible. If these triggers occur while waiting for sync on an ADV*_IND packet,
the operation ends immediately. If they occur at another time, the operation continues until the scan would
otherwise be resumed, and then ends. If the immediate command CMD_STOP is received by the radio
CPU, it has the same meaning as the end trigger occurring, except that the status code after ending is
CMD_DONE_STOPPED. The differences between the two triggers are the status and result at the end of
the operation. Typically, timeoutTrigger is used at the end of a scan window, while endTrigger is used
when scanning is to end entirely.
If pParams->initConfig.bDynamicWinOffset is 1, the radio CPU performs automatic calculation of the
WinSize and WinOffset parameters in the transmitted message. WinSize is byte 7 of the payload, and
WinOffset is byte 8 and 9. The radio CPU finds the possible start times of the first connection event from
the pParams->connectTime parameter and the connection interval, which are given in units of 1.25 ms by
the interval field (byte 10 and 11) from the payload to be transmitted. The possible times of the first
SWCU117C – February 2015 – Revised September 2015
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Table 23-127. Actions on Received Packets by Initiator
CRC Result
OK
OK
NOK
OK
OK
OK
NOK
X
X
bIgnore
1
0
0
—
Copyright © 2015, Texas Instruments Incorporated
AdvA Match InitA Match
No N/A
Yes N/A
X N/A
No X
Yes No
Yes Yes
X X
X X
N/A N/A
Description
Continue scanning
Send CONNECT_REQ and end operation
Continue scanning
Stop receiving packet, then continue scanning
Bluetooth Low Energy
Action
Number
1
2
3
1
1
2
3
4
4
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