Rev. 1.00
46
March 24, 2020
Rev. 1.00
47
March 24, 2020
BS83A04C
4-Key Enhanced Touch I/O Flash MCU
BS83A04C
4-Key Enhanced Touch I/O Flash MCU
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 name PA. 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
Name
Bit
7
6
5
4
3
2
1
0
PA
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PAC
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
PAPU
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
PAWU
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
I/O Logic Function Register List
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, all I/O pins, when
configured as an input have the capability of being connected to an internal pull-high resistor. These
pull-high resistors are selected using the LVPUC and PAPU registers, and are implemented using
weak PMOS transistors. The PAPU register is used to determine whether the pull-high function
is enabled or not while the LVPUC register is used to select the pull-high resistors value for low
voltage power supply applications.
Note that the pull-high resistor can be controlled by the relevant pull-high control register only
when the pin-shared functional pin is selected as an input or NMOS output. Otherwise, the pull-high
resistors cannot be enabled.
• PAPU Register
Bit
7
6
5
4
3
2
1
0
Name
PAPU7
PAPU6
PAPU5
PAPU4
PAPU3
PAPU2
PAPU1
PAPU0
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
PAPU7~PAPU0
: PA7~PA0 pull-high function control
0: Disable
1: Enable