HT45F43 datasheet(57/152 Pages) HOLTEK

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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 devices provide 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

²MOV A,[m]², where m denotes the port address. For output operation, all the data is latched and

remains unchanged until the output latch is rewritten.

Name

Bit

76543210

PAWU

PAPU

PAC

PBPU

PBC

PCPU

PCC

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 selectable

via a register known as PAPU, PBPU and PCPU located in the Data Memory. The pull-high resistors are

implemented using weak PMOS transistors.

HT45F23/HT45F43

8-Bit Flash MCU with Op Amps & Comparators

Rev. 1.20

September 15, 2011

HT45F43 датащи(PDF) 57 Page - Holtek Semiconductor Inc