Tx Flow - Texas Instruments CC253x User Manual

Transmit Mode
No command
strobe processor
STXON
(SAMPLED_CCA = 1)
TX completes?
Yes
TX_FRM_DONE
Frame transmitted successfully
Between two transmissions, there can be multiple other activities such as frame reception, RX FIFO access, and acknowledgment transmission (using SACK,
SACKPEND, or AUTOACK), or idle periods (random backoffs). This has no side effects on the state of the TX buffer.
The placement of the SFLUSHTX strobe in the diagram shows the latest point in time where this strobe can be executed. If fewer special cases is desired, it is
always possible to use the SFLUSHTX strobe and then load or reload TXBUF with the next frame to be transmitted.
Next time...
To retransmit the
To transmit a
current frame...
different frame...
Restart from the Restart from the
top of the diagram top of the diagram
Do not write Write the new
frame to the TX
anything to the TX
buffer
buffer
(before, after, or in
parallel with the
TX strobe)
220
CC253x Radio
Unslotted command
strobe processor
(SAMPLED_CCA = 1)
STXONCCA
Yes
TX started?
(SAMPLED_CCA = 0)
Why?
No
TX_UNDERFLOW
Error condition
To retransmit or
transmit a
different frame...
SFLUSHTX
Restart from the
top of the diagram
Write the next
frame to the TX
buffer
(before, after, or in
parallel with the
TX strobe)
Figure 23-6. TX Flow
Copyright © 2009–2014, Texas Instruments Incorporated
Slotted command
strobe processor
SSAMPLECCA
Yes
Success?
No
(SAMPLED_CCA = 0)
No
TX is aborted by
SRXON,
STXON or SRFOFF
Incomplete or no frame transmission
Next time...
To (re)transmit
what is To transmit a
currently in different frame...
the TX buffer...
Restart from the
SFLUSHTX
top of the diagram
If anything is
written to the TX
buffer, it is
Restart from the
appended to the
top of the diagram
current data.
Write the new
frame to the TX
buffer
before, after, or in
parallel with the
TX strobe)
Data buffering
Write a frame to the
TX buffer using:
- TXBUF
- TXBUFCP
- Memory access
- A combination of
these methods
This can be done
before, after, or in
parallel with the TX
strobe.
TX buffer overfilled
TX_OVERFLOW
Error condition
(left side of the flow
diagram should be
ignored because the
TX buffer is corrupted.)
To retransmit or
transmit a
different frame...
SFLUSHTX
Restart from the
top of the diagram
Write the next
frame to the TX
buffer
before, after, or in
parallel with the
TX strobe)
SWRU191F – April 2009 – Revised April 2014
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