HT46R068B/HT46R069B
Enhanced A/D Type 8-bit OTP MCU
● LVDC Register
Bit
Name
R/W
7
6
5
LVDC
R
4
LVDEN
R/W
0
3
2
1
0
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
POR
0
Bit 7~6
unimplemented, read as "0"
Bit 5
LVDO: LVD Output Flag
0: No Low Voltage Detect
1: Low Voltage Detect
Bit 4
LVDEN: Low Voltage Detector Control
0: Disable
1: Enable
Bit 3~0:
unimplemented, read as "0"
LVD Operation
The Low Voltage Detector function operates by comparing the power supply voltage, VDD, with a
pre-specified voltage level voltage level setup using a configuration option. When the power sup-
ply voltage, VDD, falls below this pre-determined value, the LVDO bit will be set high indicating a
low power supply voltage condition. The Low Voltage Detector function is supplied by a reference
voltage which will be automatically enabled. When the device is powered down the low voltage
detector will remain active if the LVDEN bit is high. After enabling the Low Voltage Detector, a
time delay tLVDS should be allowed for the circuitry to stabilise before reading the LVDO bit. Note
also that as the VDD voltage may rise and fall rather slowly, at the voltage nears that of VLVD,
there may be multiple bit LVDO transitions.
V
D
D
V
L
D
V
L
D
V
N
E
L
D
V
O
t
L
D
V
S
LVD Operation
Configuration Options
Configuration options refer to certain options within the MCU that are programmed into the OTP
Program Memory device during the programming process. During the development process,
these options are selected using the HT-IDE software development tools. As these options are
programmed into the device using the hardware programming tools, once they are selected they
can not be changed later by the application software. All options must be defined for proper system
function, the details of which are shown in the table.
No.
Oscillator Options
High Speed Sꢂstem Oscillatoꢁ Selection - fH:
Options
1. HXT
ꢃ. ERC
3. HIRC
1
Low Speed Sꢂstem Oscillatoꢁ Selection - fL:
ꢃ
1. LXT
ꢃ. LIRC
Rev. 1.00
104
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HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
