Interrupts Generated By Source Address Matching - Texas Instruments CC253x User Manual

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When There Is No Source Address:
SFD LEN
SFD
Interrupt
When There Is a Source Address:
SFD LEN
SFD
Interrupt
Figure 23-14. Interrupts Generated by Source Address Matching
Tips and Tricks
• The source address table can be modified safely during frame reception. If one address replaces
another while the receiver is active, the corresponding enable bit should be turned off during the
modification. This prevents the RF Core from using a combination of old and new values, because it
only considers entries that are enabled throughout the whole source matching process.
The following measures can be taken to avoid the next received frame overwriting the results from source
address matching:
• Use the appended SRCRESINDEX result instead of the value written to RAM (this is the
recommended approach).
• Read the results from RAM before RX_FRM_ACCEPTED occurs in the next received frame. For the
shortest frame type, this happens after the sequence number, so the total available time (absolute
worst-case with a small safety margin) becomes:
16 μs (required preamble) + 32 μs (SFD) + 128 μs (4 bytes) = 176 μs
• To increase the available time, clear the FSMCTRL.RX2RX_TIME_OFF bit. This adds another 192 μs,
for a total of 368 μs. This also reduces the risk of RX overflow.
SWRU191F – April 2009 – Revised April 2014
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FCF + SEQ + Destination
SRC_MATCH_DONE
RX_FRM_ACCEPTED
Interrupt
FCF + SEQ + Destination +
Source PAN ID
RX_FRM_ACCEPTED
Interrupt
Copyright © 2009–2014, Texas Instruments Incorporated
- - - - -
Interrupt
Source
- - - - -
Address
SRC_MATCH_FOUND interrupt
may occur during this interval
SRC_MATCH_DONE interrupt
occurs during this interval
Receive Mode
Last
Byte
RX_FRM_DONE
Interrupt
Last
Byte
RX_FRM_DONE
Interrupt
M0113-01
229
CC253x Radio