CC2430 Datasheet, PDF (179/234 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
SLOTTED_ACK = 0
PPDU
Last _sPyPmDbUol
Acknowledge
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 51: 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 52. 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 16.
The voltage regulator for the radio is
enabled by setting the RF register bit
RFPWR.RREG_RADIO_PD high. 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 142). This SFR register can be
polled when waiting for the oscillator to
start.
For test purposes, the frequency
synthesizer (FS) can also be manually
calibrated and started by using the
STXCALN or ISTXCALN command strobe
(see section 0 and 0). This will not start a
transmission before a STXON command
strobe is issued. This is not shown in
Figure 52.
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 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A
Page 179 of 232