HT66F016 View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT66F016' PDF : 116 Pages View PDF
HT66F016/HT66F017/HT68F016/HT68F017
HT66F016R/HT66F017R/HT68F016R/HT68F017R
Pin-remapping Functions
The flexibility of the microcontroller range is greatly enhanced by the use of pins that have more than one function. Limited
numbers of pins can force serious design constraints on designers but by supplying pins with multi-functions, many of
these difficulties can be overcome. The way in which the pin function of each pin is selected is different for each function
and a priority order is established where more than one pin function is selected simultaneously. Additionally there is a
PRM register to establish certain pin functions. Generally speaking, the analog function has higher priority than the digital
function. However, if more than two analog functions are enabled and the analog signal input comes from the same exter-
nal pin, the analog input will be internally connected to all of these active analog functional modules.
Pin-remapping Registers
The limited number of supplied pins in a package can impose restrictions on the amount of functions a certain device
can contain. However by allowing the same pins to share several different functions and providing a means of function
selection, a wide range of different functions can be incorporated into even relatively small package sizes.
· PRM Register
Bit
Name
R/W
POR
7
PRML3
R/W
0
6
PRML2
R/W
1
5
PRML1
R/W
0
4
PRML0
R/W
1
3
PRMS3
R/W
0
2
PRMS2
R/W
0
Bit 7~4
Bit 3
Bit 2
Bit 1~0
PRML3~PRML0: pin-remapping function lock bits (default: 0101)
1010: PRM register write operation is enabled
Others: PRM register write operation is disabled
PRMS3: INT1 pin-remapping function selection bit
0: INT1 on PA5
1: INT1 on PA4
PRMS2: INT0/TCK1 pin-remapping function selection bit
0: INT0 on PA3, TCK1 on PA3
1: INT0 on PA2, TCK1 on PA2
PRMS1~PRMS0: pin-remapping function selection bits
For HT66F017, HT68F017
0: TP0 on PA3, TP1/TCK0 on PA4
1: TP0 on PB0, TP1/TCK0 on PB1
2: TP0 on PA5, TP1/TCK0 on PA6
3: TP0 on PA2, TP1/TCK0 on PA7
For HT66F016, HT68F016
0: TP1 on PA4
1: TP1 on PB1
2: TP1 on PA6
3: TP1 on PA7
1
PRMS1
R/W
0
0
PRMS0
R/W
0
I/O Pin Structures
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.
Programming Considerations
Within the user program, one of the first things to con-
sider 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 and PBC, are then pro-
grammed to setup some pins as outputs, these output
pins will have an initial high output value unless the as-
sociated port data registers, PA and PB, are first pro-
grammed. 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 reg-
ister 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 re-
write this data back to the output ports.
Rev. 1.40
48
November 22, 2016
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