Texas Instruments SimpleLink CC2620 Technical Reference Manual page 1534

IEEE 802.15.4
Table 23-80. Conditions for Incrementing Counters and Raising Interrupts for RX
Condition
ACK frame received with CRC OK and bIgnore = 0
Data frame received with CRC OK and bIgnore = 0
MAC command frame received with CRC OK and bIgnore = 0
Frame with reserved frame type received with CRC OK and
bIgnore = 0
Frame received with CRC OK and bIgnore = 1
The first RX data entry in the RX queue changed state to finished
When a frame has been received, the RSSI observed while receiving the frame is written to
pOutput->lastRssi. If the frame was a beacon frame accepted by the frame filtering and with CRC OK, the
timestamp at the beginning of the frame is written to pOutput ->beaconTimeStamp. If the timestamp is
appended to the RX entry element (see
beacon frame.
After a packet has been received, the radio CPU either restarts sync search or sends an acknowledgment
frame. The conditions for the latter are as given in
23.5.4.1.3 ACK Transmission
After a packet has been received, the radio CPU initiates transmission of an acknowledgment frame,
given that all of the following conditions are satisfied:
• Auto ACK is enabled by frameFiltOpt.autoAckEn = 1
• The frame is accepted by frame filtering (bIgnore = 0)
• The frame is a data frame or a MAC command frame
• The destination address is not the broadcast address
• The ACK request bit of the FCF is set
• The CRC check is passed (bCrcErr = 0)
• The frame fits in the receive queue
The transmit time of the ACK packet is timed by the radio CPU, depending on frameFiltOpt.slottedAckEn.
If this bit is 0, the ACK packet is transmitted 192 µs after the end of the received packet. Otherwise,
slotted ACK is used. Assume that the received packet started on a backoff-slot boundary. The ACK frame
then starts a whole number of backoff periods later than the start of the received frame, at the first backoff
boundary following at least one TurnaroundTime-symbol period after the end of the received frame.
The contents of the automatically transmitted ACK frame are as follows:
• The PHY header is 0x05
• The PHY payload consists of a 3-byte MAC header and a 2-byte MAC footer
• The MAC header starts with the 2-byte FCF with the following fields:
– The Frame Type subfield is 010b
– The Frame Pending subfield is set as described in
– The remaining subfields are set to all zeros
• The next byte in the MAC header is the sequence number, which is set equal to the sequence number
of the received frame
• The MAC footer is the FCS, which is calculated automatically
After the ACK frame has been transmitted, a TX_ACK interrupt is raised. The radio CPU then enables the
receiver again.
1534
Radio
Operation (continued)
Counter Incremented
nRXAck
nRXData
nRXMacCmd
nRXReserved
nRXIgnored
—
Section 23.6.3.1), these two timestamps are the same for a
Section
Copyright © 2015, Texas Instruments Incorporated
23.5.4.1.3.
Section 23.5.4.1.1.2
SWCU117C – February 2015 – Revised September 2015
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Interrupt Generated
RX_OK
RX_OK
RX_OK
RX_OK
RX_IGNORED
RX_ENTRY_DONE