mc68hc908kx8 Freescale Semiconductor, Inc, mc68hc908kx8 Datasheet - Page 21

• Manufacturer Part Number: mc68hc908kx8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

1.4.2 Oscillator Pins (OSC1 and OSC2)
The OSC1 and OSC2 pins are available through programming options in the configuration register. These
pins then become the connections to an external clock source or crystal/ceramic resonator. PTB7 and
PTB6 are not available for the crystal/ceramic resonator option and PTB6 is unavailable for the external
clock source option.
1.4.3 External Interrupt Pin (IRQ1)
IRQ1 is an asynchronous external interrupt pin with an internal pullup resistor. See
Interrupt
1.4.4 Port A Input/Output (I/O) Pins (PTA4/KBD4–PTA0/KBD0)
PTA4/KBD4–PTA0/KBD0 is a 5-bit special-function port that shares its pins with the keyboard interrupt
(KBI) module and the 2-channel timer module (TIM).
1.4.5 Analog Reference Pin (V
The V
voltage is supplied through a double-bond to the V
ADC parameters.
1.4.6 Port B Input/Output (I/O) Pins (PTB7/(OSC2)/RST–PTB0/AD0)
PTB7/(OSC2)/RST–PTB0/AD0 are general-purpose bidirectional I/O port pins, all sharing special
functions.
Freescale Semiconductor
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Any or all of the port A pins can be programmed to serve as keyboard interrupt pins. The respective
pin utilizes an internal pullup resistor when enabled. See
(KBI).
Each port A pin contains a software selectable internal pullup resistor when the general-function
I/O port is configured as an input. See
resistor is automatically disabled once a TIM special function is enabled for that pin.
All port A pins are high-current source/sink pins.
PTB7 and PTB6 share with the on-chip oscillator circuit through configuration options. See
External Clock
PTB5 and PTB4 share with the SCI module. See
Module
PTB3–PTB0 share with the ADC module. See
(IRQ).
pin is the analog reference voltage for the analog-to-digital converter (ADC) module. The
(SCI).
Any unused inputs and I/O ports should be tied to an appropriate logic level
(either V
require termination, termination is recommended to reduce the possibility
of static damage.
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
Generator.
DD
or V
SS
). Although the I/O ports of the MC68HC908KX8 do not
REFH
)
Chapter 11 Input/Output (I/O) Ports
NOTE
DD
Chapter 3 Analog-to-Digital Converter
pin. See
Chapter 12 Serial Communications Interface
Chapter 17 Electrical Specifications
Chapter 9 Keyboard Interrupt Module
(PORTS). The pullup
Chapter 8 External
Pin Assignments
(ADC).
7.3.3
for
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