HT46R064B/065B/066B
Port A Wake-up
Input/Output Ports
If the HALT instruction is executed, the device will enter
the Idle/Sleep Mode, where the system clock will stop
resulting in power being conserved, a feature that is im-
portant 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 PA0~PA7 pins from high to low. After a HALT instruc-
tion forces the microcontroller into entering the
Idle/Sleep Mode, the processor will remain idle or in a
low-power state until the logic condition of the selected
wake-up pin on Port A changes from high to low. This
function is especially suitable for applications that can
be woken up via external switches. Note that pins PA0 to
PA7 can be selected individually to have this wake-up
feature using an internal register known as PAWK, lo-
cated in the Data Memory.
Holtek microcontrollers offer considerable flexibility on
their I/O ports. Most pins can have either an input or out-
put designation under user program control. Addi-
tionally, as there are pull-high resistors and wake-up
software configurations, the user is provided with an I/O
structure to meet the needs of a wide range of applica-
tion possibilities.
For input operation, these ports are non-latching, which
means the inputs must be ready at the T2 rising edge of
instruction ²MOV A,[m]², where m denotes the port ad-
dress. For output operation, all the data is latched and
remains unchanged until the output latch is rewritten.
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 resis-
tors, when configured as an input have the capability of
being connected to an internal pull-high resistor. These
pull-high resistors are selectable via a register known as
PAPU, PBPU, PCPU, PDPU, PEPU and PFPU located in
the Data Memory. The pull-high resistors are imple-
mented using weak PMOS transistors. Note that pin PA7
does not have a pull-high resistor selection.
·
PAWK, PAC, PAPU, PBC, PBPU, PCC, PCPU, PDC, PDPU Register
¨
HT46R064B
Bit
Register
Name
POR
7
6
5
4
3
2
1
0
PAWK
PAC
00H
FFH
00H
3FH
00H
FFH
00H
PAWK7 PAWK6 PAWK5 PAWK4 PAWK3 PAWK2 PAWK1 PAWK0
PAC7
¾
PAC6
PAPU6
¾
PAC5
PAPU5
PBC5
PBPU5
¾
PAC4
PAPU4
PBC4
PBPU4
¾
PAC3
PAPU3
PBC3
PAC2
PAPU2
PBC2
PAC1
PAPU1
PBC1
PAC0
PAPU0
PBC0
PAPU
PBC
¾
PBPU
PCC
PBPU3
PCC3
PBPU2
PCC2
PBPU1
PCC1
PBPU0
PCC0
¾
¾
¾
¾
PCPU
PCPU3
PCPU2
PCPU1
PCPU0
¾
¾
¾
¾
²¾² Unimplemented, read as ²0²
PAWKn: PA wake-up function enable
0: disable
1: enable
PACn/PBCn/PCCn: I/O type selection
0: output
1: input
PAPUn/PBPUn/PCPUn: Pull-high function enable
0: disable
1: enable
Rev. 1.00
36
April 8, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
