S3C8245/P8245/C8249/P8249 VOLTAGE LEVEL DETECTOR
18-1
18 VOLTAGE LEVEL DETECTOR
OVERVIEW
The S3C8245/C8249 micro-controller has a built-in VLD (Voltage Level Detector) circuit which allows detection of
power voltage drop or external input level through software. Turning the VLD operation on and off can be controlled by
software. Because the IC consumes a large amount of current during VLD operation. It is recommended that the
VLD operation should be kept OFF unless it is necessary. Also the VLD criteria voltage can be set by the software.
The criteria voltage can be set by matching to one of the 4 kinds of voltage below that can be used.
2.2 V, 2.4 V, 3.0 V or 4.0 V (VDD reference voltage), or external input level (External reference voltage)
The VLD block works only when VLDCON.2 is set. If VDD level is lower than the reference voltage selected with
VLDCON.1–.0, VLDCON.3 will be set. If VDD level is higher, VLDCON.3 will be cleared. When users need to
minimize current consumption, do not operate the VLD block.
Voltage
Level
Detector VLDCON.3
VLD Out
VLDCON.4 MUX
VLDCON.2
VLD Run
Voltage
Level
Setting
P2CONH.7-.6
ExtRef/P2.7
ExtRef Input
Enable
VLDCON.1
VLDCON.0
Set the Level
V
DD
Pin
f
VLD
Figure 18-1. Block Diagram for Voltage Level Detect