EM2420 ETC [List of Unclassifed Manufacturers], EM2420 Datasheet - Page 42

• Manufacturer Part Number: EM2420
• Description: 2.4 GHz IEEE 802.15.4 / ZigBee RF Transceiver
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Radio control state machine
The EM2420 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 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
9.
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.
Ember Part Number: 120-0049-000C
refer
to
the
state
/ SXOSCOFF
number
EM2420 Datasheet
For
synthesizer (FS) can also be manually
calibrated and started by using the
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 EM2420 is in Power Down
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, the EM2420 can remain in Power
Down until a transmission session is
requested.
As also described in the 4-wire Serial
Configuration and Data Interface section
on page 25, the crystal oscillator must be
running in order to have access to the
RAM and FIFOs.
test
purposes,
EM2420
the
Page 42 of 89
frequency