HT45F12_12 Datasheet, PDF (52/103 Pages) Holtek Semiconductor Inc – 8-Bit Flash MCU with Op Amps & Comparators

HT45F12
8-Bit Flash MCU with Op Amps & Comparators
Input/Output Ports
Holtek microcontrollers offer considerable flexibility on their I/O ports. With the input or output
designation of every pin fully under user program control, pull-high selections for all ports and
wake-up selections on certain pins, the user is provided with an I/O structure to meet the needs of a
wide range of application possibilities.
The device provides bidirectional input/output lines labeled with port names PA~PC. These I/O
ports are mapped to the RAM Data Memory with specific addresses as shown in the Special Purpose
Data Memory table. All of these I/O ports can be used for input and output operations. For input
operation, these ports are non-latching, which means the inputs must be ready at the T2 rising edge
of instruction “MOV A, [m]”, where m denotes the port address. For output operation, all the data is
latched and remains unchanged until the output latch is rewritten.
Register
Bit
Name
7
6
5
4
3
2
1
0
PAWU
D7
D6
D5
D4
D3
D2
D1
D0
PAPU
D7
D6
D5
D4
D3
D2
D1
D0
PA
D7
D6
D5
D4
D3
D2
D1
D0
PAC
D7
D6
D5
D4
D3
D2
D1
D0
PBPU
—
D6
—
—
D3
D2
D1
D0
PB
—
D6
—
—
D3
D2
D1
D0
PBC
—
D6
—
—
D3
D2
D1
D0
PCPU
—
D6
D5
D4
—
—
D1
D0
PC
—
D6
D5
D4
—
—
D1
D0
PCC
—
D6
D5
D4
—
—
D1
D0
Pull-high Resistors
Many product applications require pull-high resistors for their switch inputs usually requiring the use
of an external resistor. To eliminate the need for these external resistors, when configured as an input
have the capability of being connected to an internal pull-high resistor. These pull-high resistors are
selected using registers PAPU~PCPU, and are implemented using weak PMOS transistors.
PAPU Register
Bit
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
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
Port A bit7~ bit 0 Pull-High Control
0: Disable
1: Enable
Rev. 1.20
52
February 27, 2013