Si1000/1/2/3/4/5
Temperature Measurement with ADC8
300
250
200
150
100
Sensor Range 0
Sensor Range 1
Sensor Range 2
Sensor Range 3
50
0
-40
-20
0
20
40
60
80
100
Temperature [Celsius]
Figure 23.22. Temperature Ranges using ADC8
23.8.5. Low Battery Detector
A low battery detector (LBD) with digital read-out is integrated into the chip. A digital threshold may be pro-
grammed into the lbdt[4:0] field in "Register 1Ah. Low Battery Detector Threshold". When the digitized bat-
tery voltage reaches this threshold an interrupt will be generated on the nIRQ pin to the microcontroller.
The microcontroller can confirm source of the interrupt by reading "Register 03h. Interrupt/Status 1" and
“Register 04h. Interrupt/Status 2.”
If the LBD is enabled while the chip is in SLEEP mode, it will automatically enable the RC oscillator which
will periodically turn on the LBD circuit to measure the battery voltage. The battery voltage may also be
read out through "Register 1Bh. Battery Voltage Level" at any time when the LBD is enabled. The low bat-
tery detect function is enabled by setting enlbd=1 in "Register 07h. Operating Mode and Function Control
1".
D7
D6
D5
D4
D3
D2
D1
D0
POR
Def.
Add R/W Function/Description
1A
1B
R/W
R
Low Battery Detector
Threshold
lbdt[4] lbdt[3] lbdt[2] lbdt[1] lbdt[0]
vbat[4] vbat[3] vbat[2] vbat[1] vbat[0]
14h
Battery Voltage Level
0
0
0
—
The LBD output is digitized by a 5-bit ADC. When the LBD function is enabled (enlbd = 1 in "Register 07h.
Operating Mode and Function Control 1") the battery voltage may be read at anytime by reading "Register
1Bh. Battery Voltage Level." A battery voltage threshold may be programmed in “Register 1Ah. Low Bat-
tery Detector Threshold". When the battery voltage level drops below the battery voltage threshold an
interrupt will be generated on nIRQ pin to the microcontroller if the LBD interrupt is enabled in “Register
274
Rev. 1.0
SILICON [ SILICON ]
