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Rev. 1.00
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Input/Output Ports
P0WAKE Register – Port 0 Wake-up
P0WAKE Register
SFR Address: 91h
Bit
7
6
5
4
3
2
1
0
Name
P07WU
P06WU
P0�WU
P04WU
P03WU
P0�WU
P01WU
P00WU
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
P0WAKE:
Port 0 bit 7~bit 0 Wake-up Control
0: Disable
1: Enable
When the device enters the IDLE or Power-Down Mode, the system clock will stop resulting in
power being conserved, a feature that is important for battery and other low-power applications.
Various methods exist to wake-up the microcontroller, one of which is to change the logic condition
on one of the P0.0~P0.7 pins to a low level. Note that the Port 0 wake-up functions are triggered
by a low logic level and not by a falling edge. This Port 0 wake-up function is especially suitable
for applications that can be woken up via external switches. The P0 wake up pins can be selected
individually to have this wake-up feature using the P0WAKE, register.
SRCR Register – Slew Rate Control
SRCR Register
SFR Address: A4h
Bit
7
6
5
4
3
2
1
0
Label
—
—
SRCR.�
SRCR.4
SRCR.3
SRCR.�
SRCR.1
SRCR.0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~6
Unimplemented, read as “0”
Bit 5
SRCR.5:
P5 [7:0] Slew Control Enable
0: Fast
1: Slow
Bit 4
SRCR.4:
P4 [7:0] Slew Control Enable
0: Fast
1: Slow
Bit 3
SRCR.3:
P3 [7:0] Slew Control Enable
0: Fast
1: Slow
Bit 2
SRCR.2:
P2 [7:0] Slew Control Enable
0: Fast
1: Slow
Bit 1
SRCR.1:
P1 [7:0] Slew Control Enable
0: Fast
1: Slow
Bit 0
SRCR.0:
P0 [7:0] Slew Control Enable
0: Fast
1: Slow
The port pins, when setup as outputs, can be selected to have either a fast or slow slew rate. To
minimise noise generation due to fast switching of the output drivers, it may be advisable to select
the slower slew rate. The slew rates are selected port wide, individual pins cannot be selected to
have either fast or slow slew rates.