CC2420 Chipcon AS, CC2420 Datasheet - Page 50

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

The battery monitor is controlled through
the BATTMON control register. The battery
monitor is enabled and disabled using the
BATTMON.BATTMON_EN control bit. The
voltage regulator must also be enabled
when using the battery monitor.
The battery monitor status bit is available
in the BATTMON.BATTMON_OK status bit.
This bit is high when the VREG_IN input
voltage is higher than the toggle voltage
V
The battery monitor toggle voltage is set in
the 5-bit BATTMON.BATTMON_VOLTAGE
control bits. BATTMON_VOLTAGE is an
unsigned, positive number from 0 to 31.
The toggle voltage is given by:
Chipcon AS SmartRF ® CC2420 Preliminary Datasheet (rev 1.0), 2003-11-17
V
toggle
toggle
.
=
. 1
25
BATTMON.BATTMON_EN
V
⋅
72
−
BATTMON_VO
reference
Figure 27. Battery monitor, simplified schematic
27
bandgap
Internal
voltage
LTAGE
1.25 V
SmartRF
VREG_IN
Alternatively, for a desired toggle voltage,
BATTMON_VOLTAGE
according to:
The voltage regulator must be enabled for
at
measurement. After being enabled, the
BATTMON_OK status bit need 2 µs to
settle
programmed.
The main performance characteristics of
the battery monitor is shown in the
Electrical Specifications section on page
8.
BATTMON_VO
least
BATTMON.BATTMON_VOLTAGE[4:0]
BATTMON.BATTMON_OK
for
LTAGE
100
each
=
®
µs
72
new
−
27
should
before
CC2420
⋅
V
. 1
25
toggle
toggle
V
Page 50 of 85
the
be
voltage
first
set