CC2500
SWRS040C
Page 46 of 89
23 Voltage Regulators
CC2500
contains several on-chip linear voltage
regulators, which generate the supply voltage
needed
by
low-voltage
modules.
These
voltage regulators are invisible to the user, and
can be viewed as integral parts of the various
modules. The user must however make sure
that
the
absolute
maximum
ratings
and
required pin voltages in Table 1 and Table 13
are not exceeded. The voltage regulator for
the
digital
core
requires
one
external
decoupling capacitor.
Setting the
CSn
pin low turns on the voltage
regulator to the digital core and starts the
crystal oscillator. The
SO
pin on the SPI
interface must go low before the first positive
edge of
SCLK
(setup time is given in Table
16).
If the chip is programmed to enter power-down
mode, (
SPWD
strobe issued), the power will be
turned off after
CSn
goes high. The power and
crystal oscillator will be turned on again when
CSn
goes low.
The voltage regulator output should only be
used for driving the
CC2500
.
24 Output Power Programming
The RF output power level from the device has
two levels of programmability, as illustrated in
Figure 21.
The RF output power level from the device is
programmed through the
PATABLE
register.
If 2-FSK, GFSK or MSK modulation is
used
the
desired
output
power
is
programmed to index 0 in the
PATABLE
register (
PATABLE(0)[7:0]
). The 3-bit
value shall be set to 0
(reset default value).
If OOK modulation is used the desired
output power for the logic 0 and logic 1
power levels are programmed to index 0
and index 1 in the
PATABLE
register
respectively
(
PATABLE(0)[7:0]
and
PATABLE(1)[7:0]
).
The
3-bit
value shall be set to
1.
Table 31 contains recommended
PATABLE
settings
for
various
output
levels
and
frequency bands. See Section 10.6 on page
24 for
PATABLE
programming details. The
SmartRF
Studio software [5] should be used
to obtain optimum
PATABLE
settings for
various output powers.
PATABLE
must be programmed in burst mode
if writing to other entries than
PATABLE(0)
(OOK modulation). Note that all content of the
PATABLE
, except for the first byte (index 0) is
lost when entering the SLEEP state.
Содержание CC2500
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