Rev. 1.50
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Rev. 1.50
59
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HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
LVR
Internal Reset
t
RSTD
+ t
SST
Note: t
RSTD
is power-on delay with typical time = 50 ms
Low Voltage Reset Timing Chart
•
LVRC Register
Bit
7
6
5
4
3
2
1
0
Name
LVS�
LVS6
LVS5
LVS4
LVS3
LVS�
LVS1
LVS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
0
1
0
1
0
1
Bit 7~0
LVS7~LVS0
: LVR voltage select
01010101: 2.1V
00110011: 2.55V
10011001: 3.15V
10101010: 3.8V
Other values: Generates a MCU reset – register is reset to POR value
When an actual low voltage condition occurs, as specified by one of the four defined
LVR voltage value above, an MCU reset will generated. The reset operation will be
activated after 2~3 f
LIRC
clock cycles. In this situation the register contents will remain
the same after such a reset occurs.
Any register value, other than the four defined register values above, will also result
in the generation of an MCU reset. The reset operation will be activated after 2~3 f
LIRC
clock cycles. However, in this situation the register contents will be reset to the POR
value.
•
CTRL Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
—
—
—
LVRF
LRF
WRF
R/W
R/W
—
—
—
—
R/W
R/W
R/W
POR
0
—
—
—
—
x
0
0
“x”: �nknown
Bit 7
FSYSON
: f
SYS
Control in IDLE Mode
Described elsewhere.
Bit 6~3
Unimplemented, read as “0”
Bit 2
LVRF
: LVR function reset flag
0: Not occurred
1: Occurred
This bit is set to 1 when a specific low voltage reset condition occurs. Note that this bit
can only be cleared to 0 by the application program.
Bit 1
LRF
: LVR control register software reset flag
0: Not occurred
1: Occurred
This bit is set to 1 by the LVRC control register contains any undefined LVR voltage
register values. This in effect acts like a software-reset function. Note that this bit can
only be cleared to 0 by the application program.
Bit 0
WRF
: WDT control register software reset flag
Described elsewhere.