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Link Layer Engine
25.9.1 Command Register
The command register
RFST
can be used for sending commands to the LLE and the FIFOs. Commands
in the range 0x80
–
0xFF are commands to the FIFOs, see
. Other commands are
commands to the LLE.
The commands are listed in
. There are commands for starting receive and transmit modes. In
addition, there is a command CMD_SHUTDOWN to stop the radio operation and end the task directly.
The commands CMD_SEND_EVENT1 and CMD_SEND_EVENT2 do the same action as receiving a
Timer 2 event 1 or event 2
If an unknown command is entered, the LLE responds by generating an
LLEERR
interrupt. If a task is
running, it stops.
When sending a command to the LLE, the
RFST
register retains its value until the LLE has received the
command (but not necessarily executed it) and then is set to 0. Commands should not be sent to the LLE
unless
RFST
is 0.
Table 25-12. Commands From MCU to LL Engine via
RFST
Register
Number
Command Name
Description
0x01
CMD_SHUTDOWN
Stop operation immediately
0x02
CMD_DEMOD_TEST
Start demodulator without sync search
0x03
CMD_RX_TEST
Start demodulator and sync search
0x04
CMD_TX_TEST
Start transmitter and transmit zeros
0x05
CMD_TX_FIFO_TEST
Start transmitter and transmit from Tx FIFO
0x06
CMD_PING
Respond with a
PINGRSP
interrupt
0x08
CMD_RX
Start receive operation
0x09
CMD_TX
Start transmit operation
0x0A
CMD_TX_ON_CC
Start transmit operation on clear channel
0x0B
CMD_STOP
Gracefully stop radio task
0x21
CMD_SEND_EVENT1
Do the same action as if Timer 2 event 1 was observed
0x22
CMD_SEND_EVENT2
Do the same action as if Timer 2 event 2 was observed
0x30
CMD_FLUSH_ACK0
Flush the ACK payload buffers for address 0
0x31
CMD_FLUSH_ACK1
Flush the ACK payload buffers for address 1
0x32
CMD_FLUSH_ACK2
Flush the ACK payload buffers for address 2
0x33
CMD_FLUSH_ACK3
Flush the ACK payload buffers for address 3
0x34
CMD_FLUSH_ACK4
Flush the ACK payload buffers for address 4
0x35
CMD_FLUSH_ACK5
Flush the ACK payload buffers for address 5
0x36
CMD_FLUSH_ACK6
Flush the ACK payload buffers for address 6
0x37
CMD_FLUSH_ACK7
Flush the ACK payload buffers for address 7
25.9.2 Radio Tasks
Before starting a task, radio registers should be set up with the desired packet format, and the desired
input sensitivity and output power should be programmed. Furthermore, the sync word in use must be
programmed in the
SW0
,
SW1
,
SW2
, and
SW3
registers. If a secondary sync word is used, it must be
programmed in the
SW4
,
SW5
,
SW6
, and
SW7
registers. The RAM registers must be programmed to
configure the task. The way the task runs depends on the
PRF_TASK_CONF
register. The operation mode
is set up by the
MODE
bits of this register. A value of 00 or 01 gives basic mode and thus disables auto
ACK or auto retransmission. A value of 10 or 11 gives auto mode where auto acknowledgment or auto
retransmission can be enabled per the address in
PRF_ADDR_ENTRYn.CONF.AA
.
All tasks start with a start-of-task command from the MCU. The LLE takes
SEMAPHORE0
at this time; if the
semaphore is not available, the task ends with an error. Depending on the configuration in
PRF_TASK_CONF.START_CONF
, the LLE either starts the task immediately or waits for a Timer 2 event 1
before starting. Note that a Timer 2 event 1 may be pending from before the LLE starts waiting; in that
case, the task starts immediately. To clear a pending Timer 2 event 1, reset the LLE. To prevent
315
SWRU191C
–
April 2009
–
Revised January 2012
CC2541 Proprietary Mode Radio
Copyright
©
2009
–
2012, Texas Instruments Incorporated