Rev. 1.10
52
November 04, 2019
Rev. 1.10
53
November 04, 2019
HT45F5Q-3
Battery Charger Flash MCU
HT45F5Q-3
Battery Charger Flash MCU
Port A Wake-up
The HALT instruction forces the microcontroller into the SLEEP or IDLE Mode which preserves
power, a feature that is important for battery and other low-power applications. Various methods
exist to wake-up the microcontroller, one of which is to change the logic condition on one of the Port
A pins from high to low. This function is especially suitable for applications that can be woken up
via external switches. Each pin on Port A can be selected individually to have this wake-up feature
using the PAWU register.
Note that the wake-up function can be controlled by the wake-up control registers only when the pin
is selected as a general purpose input and the MCU enters the IDLE or SLEEP mode.
• PAWU Register
Bit
7
6
5
4
3
2
1
0
Name
PAWU7
PAWU6
PAWU5
PAWU4
PAWU3
PAWU2
PAWU1
PAWU0
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
PAWU7~PAWU0
: PA7~PA0 wake-up function control
0: Disable
1: Enable
I/O Port Control Registers
Each I/O port has its own control register known as PAC~PCC, to control the input/output
configuration. With this control register, each CMOS output or input can be reconfigured
dynamically under software control. Each pin of the I/O ports is directly mapped to a bit in its
associated port control register. For the I/O pin to function as an input, the corresponding bit of the
control register must be written as a “1”. This will then allow the logic state of the input pin to be
directly read by instructions. When the corresponding bit of the control register is written as a “0”,
the I/O pin will be setup as a CMOS output. If the pin is currently setup as an output, instructions
can still be used to read the output register. However, it should be noted that the program will in fact
only read the status of the output data latch and not the actual logic status of the output pin when the
IECM is set to “0”.
• PxC Register
Bit
7
6
5
4
3
2
1
0
Name
PxC7
PxC6
PxC5
PxC4
PxC3
PxC2
PxC1
PxC0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
1
1
1
1
1
1
1
1
PxCn
: I/O Port x Pin type selection
0: Output
1: Input
The PxCn bit is used to control the pin type selection. Here the “x” can be A, B and C.
However, the actual available bits for each I/O Port may be different.
Pin-shared 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. For these pins, the
desired function of the multi-function I/O pins is selected by a series of registers via the application
program control.
