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CC112X/CC1175
SWRU295C
Page 54 of 108
8.4
Active Modes
CC112X
has two active modes: receive (RX) and transmit (TX). These modes are activated directly by
command strobes, or automatically by eWOR (RX mode).
The MCU can manually change the state from RX to TX and vice versa by using the command
strobes. If the radio controller is currently in transmit and the
transmission will be ended and the transition to RX will be done. If the radio controller is in RX when
the
command strobes are used, the TX-on-CCA function will be used. If the channel
is clear, TX (or FSTXON state) is entered. The
PKT_CFG2.CCA_MODE
setting controls the conditions
for clear channel assessment (see Section 5.10 for more details).
command strobe can always be used to force the radio controller to go to the IDLE state.
8.4.1
RX
When RX is activated, the chip will remain in receive mode until:
A packet is received
An
SIDLE
,
, or
command strobe is being issued
The RX FIFO overflows/underflows
The RX termination timer expires
A CS or PQT based termination takes place
When a packet is successfully received, the radio controller goes to the state indicated by the
setting, i.e. IDLE, FSTXON, TX or RX. When a bad packet is received
(packet length/address/CRC error) the radio controller will either restart RX or go to IDLE depending
on the
RFEND_CFG0.TERM_ON_BAD_PACKET_EN
When an RX FIFO overflow or underflow occurs, the radio will enter RX_FIFO_ERR state. When RX
terminates due to the RX termination timer or lack of CS/PQT, the radio will enter IDLE mode (via
CALIBRATE depending on the
Please see Section 8.6 for details on which states the radio enters after RX when eWOR is used.
8.4.2
TX
Similarly, when TX is active the chip will remain in the TX state until:
The current packet has been transmitted
An
SIDLE
command strobe is being issued
The TX FIFO overflows/underflows
When a packet is successfully transmitted, the radio controller goes to the state indicated by the
setting. The possible destinations are the same as for RX.
15
strobe is issued in RX state, RX is restarted (the modulator starts searching for a
sync word). If the radio was in the middle
of a packet reception, part of the “old” packet will remain in
the RX FIFO so
should be read before strobing
to keep track of
where the old and new packets are located in the RX FIFO.