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Rev. 1.00
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Reset and Initialisation
WDTCR Register Software Reset
A WDTCR software reset will be generated when a value other than “10101” or “01010”, exist in
the highest five bits of the WDTCR register. The WRF bit in the RSTSRC register will be set high
when this occurs, thus indicating the generation of a WDTCR software reset.
WDTCR Register
SFR Address: 96h
Bit
7
6
5
4
3
2
1
0
Name
WE4
WE3
WE�
WE1
WE0
—
—
WDTCS
R/W
R/W
R/W
R/W
R/W
R/W
—
—
R/W
POR
0
1
0
1
0
—
—
0
Bit 7~3
WE4~WE0:
WDT function software control
10101: Disable
01010: Enable – default
Other values: Reset MCU
If the MCU reset is caused by WE[4:0] in WDTC software reset, the WRF flag of
RSTSRC register will be set.
Bit 2~1
Unimplemented, read as “0”
Bit 0
WDTCS:
Watchdog clock (f
WDT
) select
Described elsewhere
LVRCR Register Software Reset
An LVRCR software reset will be generated when a value other than “01010101”, “00110011”,
“10011001” and “10101010”, exist in the LVRCR register. The LRF bit in the RSTSRC register
will be set high when this occurs, thus indicating the generation of an LVRCR software reset. The
LVRCR register value will be rest to a value of 01010101B after any reset other than the LVR reset,
and will remain unchanged after an LVR reset or during a WDT time out in the Power-Down mode.
LVRCR Register
SFR Address: EAh
Bit
7
6
5
4
3
2
1
0
Name
LVS7
LVS6
LVS�
LVS4
LVS3
LVS�
LVS1
LVS0
R/W
R/W
R/W
R/W
R/W
R
R
R/W
R/W
POR
0
1
0
1
0
1
0
1
Bit 7~0
LVS7~LVS0:
LVR Voltage Select control
01010101: 2.1V – default value
00110011: 2.55V
10011001: 3.15V
10101010: 4.0V
Any other value: Generates MCU reset – register is reset to POR value