HT45R37
Pin Description
Configuration
Option
Pin Name
I/O
Description
Bidirectional 8-bit input/output port. Each individual bit on this port
can be configured as a wake-up input using the PAWU register.
Software instructions determine if the pin is a CMOS output or
Schmitt trigger input. A pull high resistor can be connected to each
pin using the PAPU register. Pins PA0, PA1, PA3, PA2, PA4, PA6
and PA7 are shared with BZ, BZ, PFD, TMR0, TMR1, INT0 and
INT1 respectively. PA7 is also pin-shared with the SPI bus data
output line, SDO. PA6 is also pin-shared with the SPI bus data line,
SDI and the I2C Bus data line SDA. PA5 is also pin-shared with the
SPI bus clock line, SCK, and the I2C Bus clock line SCL. PA4 is
also pin-shared with the SPI bus select line, SCS. The C/R to F
converter inputs RC0~RC7 are shared with pins Pins PA0~PA7
respectively.
PA0/BZ/RC0
PA1/BZ/RC1
PA2/TMR0/RC2
BZ/BZ
PFD
PA3/PFD/RC3
I/O
PA4/TMR1/SCS/RC4
PA5/SCK/SCL/RC5
PA6/INT0/SDI/SDA/RC6
PA7/INT1/SDO/RC7
SIM
RC0~RC7
Bidirectional 6-bit input/output port. Software instructions deter-
mine if the pin is a CMOS output or Schmitt trigger input. A pull
high resistor can be connected to each pin using the PBPU regis-
ter. PB is pin-shared with the A/D input pins. The A/D inputs are se-
lected via software instructions. Once selected as an A/D input,
the I/O function and pull-high resistor selections are disabled auto-
matically.
PB0/AN0~PB5/AN5
I/O
I/O
¾
Bidirectional line I/O. Software instructions determine if the pin is
an NMOS output or Schmitt Trigger input. A configuration option
determines if the pin is to be used as a RES pin or as an I/O pin.
This pin does not have an internal pull-high function.
PC0/RES
PC0 or RES
Bidirectional 8-bit input/output port. Software instructions deter-
mine if the pin is a CMOS output or Schmitt trigger input. A pull
high resistor can be connected to each pin using the PDPU regis-
ter. The PWM outputs, PWM0 and PWM1, are pin shared with pins
PD0 and PD1, the function of which is chosen using the PWM reg-
isters. PD6 is pin-shared with the Peripheral Interrupt line, PINT.
PD7 is pin-shared with the Peripheral Clock line, PCLK. The C/R to
F converter inputs RC8~RC15 are shared with pins Pins
PD0~PD7 respectively.
PD0/PWM0/RC8
PD1/PWM1/RC9
PD2/RC10~PD5/RC13
PD6/PINT/RC14
PD7/PCLK/RC15
I/O
RC8~RC15
RCOUT/IN
RREF
I
I
I
Capacitor or resistor connection pin to RC OSC/ Oscillation input.
Reference resistor connection pin
¾
¾
¾
CREF
Reference capacitor connection pin
Bidirectional 2-line I/O. Software instructions determine if the pins
are CMOS outputs or Schmitt Trigger inputs. A pull high resistor
can be connected to each pin using the PCPU register. Configura-
tion options determine if the pins are to be used as oscillator pins
or I/O pins. Configuration options also determine which oscillator
1.Int. RC OSC mode is selected. The three oscillator modes are:
PC1/OSC1
PC2/OSC2
I/O 2.Crystal OSC 1. Internal RC OSC: both pins configured as I/Os.
3.Ext. RC OSC 2. External crystal OSC: both pins configured as OSC1/OSC2.
3. External RC OSC+PC2: PC1 is configured as OSC1 pin, PC2
configured as an I/O.
If the internal RC OSC is selected, the frequency will be fixed at either
4MHz, 8MHz or 12MHz, dependent upon which configuration option
is chosen.
Rev. 1.10
3
January 29, 2010
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
