mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 103

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 12
Input/Output Ports (PORTS)
12.1 Introduction
The MC68HC908QB8, MC68HC908QB4 and MC68HC908QY8 have thirteen bidirectional pins and one
input only pin.
12.2 Port A
Port A is an 6-bit special function port that shares its pins with the keyboard interrupt (KBI) module
(see
16 Timer Interface Module
Module), the external interrupt (IRQ) pin (see
enabled using a configuration register (see
oscillator pins (see
Each port A pin also has a software configurable pullup device if the corresponding port pin is configured
as an input port.
Freescale Semiconductor
Chapter 9 Keyboard Interrupt Module
Connect any unused I/O pins to an appropriate logic level, either V
Although the I/O ports do not require termination for proper operation,
termination reduces excess current consumption and the possibility of
electrostatic damage.
PTA2 is input only.
When the IRQ function is enabled in the configuration register 2
(CONFIG2), bit 2 of the port A data register (PTA) will always read a logic 0.
In this case, the BIH and BIL instructions can be used to read the logic level
on the PTA2 pin. When the IRQ function is disabled, these instructions will
behave as if the PTA2 pin is a logic 1. However, reading bit 2 of PTA will
read the actual logic level on the pin.
Chapter 11 Oscillator Module
(TIM)), the 10-bit ADC (see
MC68HC908QB8 Data Sheet, Rev. 2
(KBI), the 4-channel timer interface module (TIM) (see
Chapter 5 Configuration Register
Chapter 8 External Interrupt
NOTE
NOTE
(OSC)).
Chapter 3 Analog-to-Digital Converter (ADC10)
(IRQ)), the reset (RST) pin
(CONFIG)) and the
DD
or V
SS
.
Chapter
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