CC2430 Datasheet, PDF (166/212 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

Radio : Radio control state machine
SLOTTED_ACK = 0
PPDU
Last _sPyPmDbUol
Acknowledge
CC2430
SLOTTED_ACK = 1
t_backoffslot = 20 sym bol periods
t_ack = 12 sym bol periods
Last _sPyPmDbUol
PPDU
Acknowledge
t_ack = 12 - 30 sym bol periods
Figure 45: Acknowledge frame timing
14.20 Radio control state machine
CC2430 has a built-in state machine that is
used to switch between different operation
states (modes). The change of state is done
either by using command strobes or by
internal events such as SFD detected in
receive mode.
The radio control state machine states are
shown in Figure 46. The numbers in brackets
refer to the state number readable in the
FSMSTATE status register. Reading the
FSMSTATE status register is primarily for test /
debug purposes. The figure assumes that the
device is already placed in the PM0 power
mode.
Before using the radio in either RX or TX
mode, the voltage regulator and crystal
oscillator must be turned on and become
stable. The voltage regulator and crystal
oscillator startup times are given in the section
7.4 on page 14.
The voltage regulator for the radio is enabled
by setting the RF register bit
RFPWR.RREG_RADIO_PD to 0. The interrupt
flag RFIF.IRQ_RREG_ON is set to 1 when the
voltage regulator has powered-up.
The crystal oscillator is controlled through the
Power Management Controller. The
SLEEP.XOSC_STB bit indicates whether the
oscillator is running and stable or not (see
page 67). This SFR register can be polled
when waiting for the oscillator to start. It
should be noted that an additional wait time
after this event until selecting XOSC as source
is needed. This is described in section
13.1.4.2.
For test purposes, the frequency synthesizer
(FS) can also be manually calibrated and
started by using the STXCALN or ISTXCALN
command strobe (see section 14.34 and Table
47). This will not start a transmission before a
STXON command strobe is issued. This is not
shown in Figure 46.
Enabling transmission is done by issuing a
STXON or STXONCCA command strobe.
Turning off RF can be accomplished by using
the SRFOFF command strobe.
After bringing the CC2430 up to Power Mode 0
(PM0) from a low-power mode e.g. Power
Mode 3 (PM3), all RF registers will retain their
values thus placing the chip ready to operate
at the correct frequency and mode. Due to the
very fast start-up time, CC2430 can remain in a
low-power mode until a transmission session
is requested.
CC2430 Data Sheet (rev. 2.1) SWRS036F
Page 166 of 211