HT66F25D View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT66F25D' PDF : 177 Pages View PDF
A/D Flash Type 8-bit MCU with EEPROM
HT66F24D/HT66F25D
• LVRC Register
Bit
7
Name
LVS7
R/W
R/W
POR
0
6
LVS6
R/W
1
5
LVS5
R/W
0
4
LVS4
R/W
1
3
LVS3
R/W
0
2
LVS2
R/W
1
1
LVS1
R/W
0
0
LVS0
R/W
1
Bit 7~0
LVS7~LVS0: LVR Voltage Select control
01010101: 2.1V
00110011: 2.55V
10011001: 3.15V
10101010: 3.8V
Any other value: Generates MCU reset
When an actual low voltage condition occurs, as specified by one of the four defined
LVR voltage values above, an MCU reset will be generated. In this situation the
register contents will remain the same after such a reset occurs.
Any register value, other than the four defined LVR values above, will also result in
the generation of an MCU reset. The reset operation will be activated after 2~3 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
Bit 7
Bit 6~3
Bit 2
Bit 1
Bit 0
FSYSON: fSYS Control in IDLE Mode
Describe elsewhere.
“—”: Unimplemented, read as 0
LVRF: LVR function reset flag
0: Not occur
1: Occurred
This bit is set to 1 when a specific Low Voltage Reset situation condition occurs. This
bit can only be cleared to 0 by the application program.
LRF: LVR Control register software reset flag
0: Not occur
1: Occurred
This bit is set to 1 if the LVRC register contains any non defined LVR voltage register
values. This in effect acts like a software reset function. This bit can only be cleared to
0 by the application program.
WRF: WDT Control register software reset flag
Describe elsewhere.
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation will perform a full reset and also the
Watchdog time-out flag TO will be set to “1”.
W D T T im e - o u t
tR S T D + tS S T
In te rn a l R e s e t
WDT Time-out Reset during Normal Operation Timing Chart
Note: tRSTD is power-on delay, typical time=16.7ms
Rev. 1.10
54
March 25, 2013
Share Link: 
