HT68F13 datasheet(56/161 Pages) HOLTEK

56 / 161 page

PDC Register

- HT68F14,HT68F15

Bit

Name

R/W

POR

Bit7~2

²¾² Unimplemented,readas ²0²

Bit1~0

I/OPortDbit1~bit0input/outputcontrol

0:output

1:input

I/OPinStructures

The accompanying diagrams illustrate the internal structures of some generic I/O pin types. As the

exact logical construction of the I/O pin will differ from these drawings, they are supplied as a guide

only to assist with the functional understanding of the I/O pins. The wide range of pin-shared

structures does not permit all types to be shown. The diagrams illustrate the I/O pin internal structures.

As the exact logical construction of the I/O pin may differ from these drawings, they are supplied as a

guide only to assist with the functional understanding of the I/O pins.

ProgrammingConsiderations

Within the user program, one of the first things to consider is port initialisation. After a reset, all of the

I/O data and port control registers will be set high. This means that all I/O pins will default to an input

state, the level of which depends on the other connected circuitry and whether pull-high selections

have been chosen. If the port control registers, PAC~PDC, are then programmed to setup some pins as

outputs, these output pins will have an initial high output value unless the associated port data

registers, PA~PD, are first programmed. Selecting which pins are inputs and which are outputs can be

achieved byte-wide by loading the correct values into the appropriate port control register or by

programming individual bits in the port control register using the

²SET [m].i² and ²CLR [m].i²

instructions. Note that when using these bit control instructions, a read-modify-write operation takes

place. The microcontroller must first read in the data on the entire port, modify it to the required new

bit values and then rewrite this data back to the output ports.

Port A has the additional capability of providing wake-up functions. When the device is in the SLEEP

or IDLE Mode, various methods are available to wake the device up. One of these is a high to low

transition of any of the Port A pins. Single or multiple pins on Port A can be setup to have this function.

Rev.1.10

February9,2011

HT68F13/HT68F14/HT68F15

EnhancedI/OFlashType MCU

HT68F13 датащи(PDF) 56 Page - Holtek Semiconductor Inc