HT46R064B/065B/066B
I/O Port Control Registers
pull-high selection, even if the PFD function has been
selected.
Each Port has its own control register, known as PAC,
PBC, PCC, PDC which controls the input/output config-
uration. With this control register, each I/O pin with or
without pull-high resistors can be reconfigured dynami-
cally under software control. For the I/O pin to function
as an input, the corresponding bit of the control register
must be written as a ²1². 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 ²0², the I/O pin will be setup as a CMOS out-
put. 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.
·
PWM Outputs
The PWM function whose outputs are pin-shared with
I/O pins. The PWM output functions are chosen using
the CTRL0 registers. Note that the corresponding bit
of the port control registers, for the output pin, must
setup the pin as an output to enable the PWM output.
If the pins are setup as inputs, then the pin will function
as a normal logic input with the usual pull-high selec-
tions, even if the PWM registers have enabled the
PWM function.
·
·
SCOM Driver Pins
Pins PB0~PB3 on Port B can be used as LCD COM
driver pins. This function is controlled using the
SCOMC register which will generate the necessary
1/2 bias signals on these four pins.
A/D Inputs
Pin-shared Functions
Each device in this series has either four or eight in-
puts to the A/D converter. All of these analog inputs
are pin-shared with I/O pins. If these pins are to be
used as A/D inputs and not as I/O pins then the corre-
sponding PCRn bits in the A/D converter control regis-
ter, ADCR, must be properly setup. There are no
configuration options associated with the A/D con-
verter. If chosen as I/O pins, then full pull-high resistor
configuration options remain, however if used as A/D
inputs then any pull-high resistor configuration options
associated with these pins will be automatically dis-
connected.
The flexibility of the microcontroller range is greatly en-
hanced by the use of pins that have more than one func-
tion. Limited numbers of pins can force serious design
constraints on designers but by supplying pins with
multi-functions, many of these difficulties can be over-
come. For some pins, the chosen function of the
multi-function I/O pins is set by configuration options
while for others the function is set by application pro-
gram control.
·
External Interrupt Input
The external interrupt pin, INT, is pin-shared with an
I/O pin. To use the pin as an external interrupt input
the correct bits in the INTC0 register must be pro-
grammed. The pin must also be setup as an input by
setting the PAC3 bit in the Port Control Register. A
pull-high resistor can also be selected via the appro-
priate port pull-high resistor register. Note that even if
the pin is setup as an external interrupt input the I/O
function still remains.
Pin Remapping Configuration - HT46R066B
The pin remapping function enables the function pins
INT, TC0 and PFD to be located on different port pins. It
is important not to confuse the Pin Remapping function
with the Pin-shared function, these two functions have
no interdependence.
The PCFG bit in the CTRL0 register allows the three
function pins INT, TC0 and PFD to be remapped to dif-
ferent port pins. After power up, this bit will be reset to
zero, which will define the default port pins to which
these three functions will be mapped. Changing this bit
will move the functions to other port pins.
·
External Timer/Event Counter Input
The Timer/Event Counter pins, TC0 and TC1 are
pin-shared with I/O pins. For these shared pins to be
used as Timer/Event Counter inputs, the Timer/Event
Counter must be configured to be in the Event Coun-
ter or Pulse Width Capture Mode. This is achieved by
setting the appropriate bits in the Timer/Event Counter
Control Register. The pins must also be setup as in-
puts by setting the appropriate bit in the Port Control
Register. Pull-high resistor options can also be se-
lected using the port pull-high resistor registers. Note
that even if the pin is setup as an external timer input
the I/O function still remains.
Examination of the pin names on the package diagrams
will reveal that some pin function names are repeated,
this indicates a function pin that can be remapped to
other port pins. If the pin name is bracketed then this in-
dicates its alternative location. Pin names without brack-
ets indicates its default location which is the condition
after Power-on.
·
PFD Output
The PFD function output is pin-shared with an I/O pin.
The output function of this pin is chosen using the
CTRL0 register. Note that the corresponding bit of
the port control register, must setup the pin as an
output to enable the PFD output. If the port control
register has setup the pin as an input, then the pin will
function as a normal logic input with the usual
PCFG Bit Status
PCFG Bit
0
1
INT/PA3
TC0/PA2
PFD/PA1
[INT]/PB5
[TC0]/PB4
[PFD]/PB3
Pin Mapping
Pin Remapping
Rev. 1.00
38
April 8, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
