Texas Instruments SimpleLink CC2620 Technical Reference Manual page 1573

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23.6.4.7 Generic Receiver Command
The generic receiver command is used to receive physical layer test packets or to receive any packet,
such as in a packet sniffer application.
A generic receiver operation is started by a CMD_BLE_GENERIC_RX command. In the command
structure, it has a pParams parameter of the type defined in
type defined in Table
trigger, then programs the frequency based on the channel parameter of the command structure. The
radio CPU sets up the access address defined in pParams->accessAddress and uses the CRC
initialization value defined in pParams->crcInit. The whitener is set up as defined in the whitening
parameter. The radio CPU then configures the receiver.
In a generic receiver operation, the only assumption made on the packet format is that the 6 LSBs of the
second received byte is a length field which indicates the length of the payload following that byte, and
that a standard BLE-type CRC is appended to the packet.
When tuned to the correct channel, the radio CPU starts listening for a packet. If sync is obtained on the
demodulator, the message is received into the RX queue (if any). If the length is greater than the
maximum allowed length for BLE advertising packets (37, but can be overridden), reception is stopped
and restarted.
If pParams->pRxQ is NULL, the received packets are be stored. The counters are still updated and
interrupts generated.
If a packet is received with CRC error, the bCrcErr bit is set. The bIgnored flag is never set for the generic
RX command.
If the packet being 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.
A trigger to end the operation is set up by pParams->endTrigger and pParams->endTime. If the trigger
defined by this parameter occurs, the radio operation ends as soon as possible. If the trigger occurs while
waiting for sync, the operation ends immediately. If the trigger occurs at another time, the operation
continues until the current packet has been fully received, 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 output structure pOutput contains fields
which give information on the command being run. The radio CPU does not initialize the fields, so this
must be done by the system CPU when a reset of the counters is desired. The fields are updated by the
radio CPU as described below. The list also indicates when interrupts are raised in the system CPU.
• If a packet is received with CRC OK, nRXOk is incremented and an RX_OK interrupt is raised.
• If a packet is received with CRC error, nRXNok is incremented and an RX_NOK interrupt is raised.
• If a packet is received and did not fit in the RX queue, nRXBufFull is incremented and an
RX_BUF_FULL interrupt is raised.
• If a packet is received, lastRssi is set to the RSSI of that packet
• If a packet is received, timeStamp is set to a timestamp of the start of than packet
• If the first RX data entry in the RX queue changed state to Finished after a packet was received, an
RX_ENTRY_DONE interrupt is raised.
After a packet has been received, reception is restarted on the same channel if pParams->bRepeat = 1,
the end event has not been observed, and the packet fits in the receive queue. If pParams->bRepeat = 0,
the operation always ends after receiving a packet.
A generic RX operation ends with one of the statuses listed in
command structure after the operation is ended indicates the reason why the operation ended. In all
cases, a COMMAND_DONE interrupt is raised. In each case, it is indicated if the result is TRUE, FALSE,
or ABORT, which decides the next action. The pNextOp field of a generic RX command structure may
point to the same command structure. That way, RX may be performed until the end trigger, or until the
RX buffer goes full.
SWCU117C – February 2015 – Revised September 2015
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23-102. At the start of a generic receiver operation, the radio CPU waits for the start
Copyright © 2015, Texas Instruments Incorporated
Table 23-96, and a pOutput parameter of the
Table 23-130. The status field of the
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