CC2420 Chipcon AS, CC2420 Datasheet - Page 39

• Manufacturer Part Number: CC2420
• Description: 2.4 GHz RF Transceiver for IEEE 802.15.4 and ZigBee
• Manufacturer: Chipcon AS

Radio control state machine
CC2420
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 23. The numbers in
brackets
readable in the FSMSTATE status register.
This functionality is primarily for test /
debug purposes.
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
Electrical Specifications section on page
8.
The crystal oscillator is controlled by
accessing the SXOSCON
command strobes. The XOSC16M_STABLE
bit in the status register returned during
address transfer indicates whether the
oscillator is running and stable or not (see
Table 5). This status register can be polled
when waiting for the oscillator to start.
Chipcon AS SmartRF ® CC2420 Preliminary Datasheet (rev 1.0), 2003-11-17
has a built-in state machine that is
refer
to
the
state
/ SXOSCOFF
number
SmartRF
For
synthesizer (FS) can also be manually
calibrated and started by
STXCAL command strobe register. This
will not start a transmission before a
STXON command strobe is issued. This is
not shown in Figure 23.
Enabling transmission is done by issuing a
STXON or STXONCCA command strobe.
Turning off RF can be accomplished by
using one of the SRFOFF or SXOSCOFF
command strobe registers.
After reset the
mode. All configuration registers can then
be programmed in order to make the chip
ready to operate at the correct frequency
and mode. Due to the very fast start-up
time,
until a transmission session is requested.
As also described in the 4-wire Serial
Configuration and Data Interface section
on page 23, the crystal oscillator must be
running in order to have access to the
RAM and FIFOs.
CC2420
test
purposes,
can remain in Power Down
CC2420
®
is in Power Down
CC2420
the
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using the
frequency