Samsung S3C8275X - Manual (Page 282)

S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X BATTERY LEVEL DETECTOR
15-1
15
BATTERY LEVEL DETECTOR
OVERVIEW
The S3C8275X/C8278X/C8274X micro-controller has a built-in BLD (Battery Level Detector) circuit which allows
detection of power voltage drop or external input level through software. Turning the BLD operation on and off can
be controlled by software. Because the IC consumes a large amount of current during BLD operation. It is
recommended that the BLD operation should be kept OFF unless it is necessary. Also the BLD criteria voltage
can be set by the software. The criteria voltage can be set by matching to one of the 3 kinds of voltage below that
can be used.
2.2 V, 2.4 V or 2.8 V (V
DD
reference voltage), or external input level (External reference voltage)
The BLD block works only when BLDCON.3 is set. If V
DD
level is lower than the reference voltage selected with
BLDCON.2–.0, BLDCON.4 will be set. If V
DD
level is higher, BLDCON.4 will be cleared. When users need to
minimize current consumption, do not operate the BLD block.
Battery
Level
Detector
BLDCON.4
BLD Out
BLDCON.5 MUX
BLDCON.3
BLD Run
Battery
Level
Setting
P2CONL.1-.0
V BLDREF /P2.0
ExtRef Input
Enable
BLDCON.2-0
Set the Level
V DD Pin
f BLD
Figure 15-1. Block Diagram for Voltage Level Detect