HT68F14 HOLTEK [Holtek Semiconductor Inc], HT68F14 Datasheet - Page 56

• Manufacturer Part Number: HT68F14
• Description: Enhanced I/O Flash Type MCU
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

Rev. 1.10
Bit 7~2
Bit 1~0
I/O Pin Structures
Programming Considerations
Name
POR
R/W
Bit
PDC Register - HT68F14, HT68F15
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.
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.
²¾² Unimplemented, read as ²0²
I/O Port D bit 1 ~ bit 0 input/output control
0: output
1: input
¾
¾
¾
7
¾
¾
¾
6
¾
¾
¾
5
56
¾
¾
¾
4
Enhanced I/O Flash Type MCU
HT68F13/HT68F14/HT68F15
¾
¾
¾
3
¾
¾
¾
2
R/W
D1
1
0
February 9, 2011
R/W
D0
0
0