Datasheet

External Interrupt (IRQ)
MC68HC908QB8 Data Sheet, Rev. 3
78 Freescale Semiconductor
Figure 8-1. Block Diagram Highlighting IRQ Block and Pin
When set, the IMASK bit in INTSCR masks the IRQ
interrupt request. A latched interrupt request is not
presented to the interrupt priority logic unless IMASK is clear.
NOTE
The interrupt mask (I) in the condition code register (CCR) masks all
interrupt requests, including the IRQ
interrupt request.
A falling edge on the IRQ
pin can latch an interrupt request into the IRQ latch. An IRQ vector fetch,
software clear, or reset clears the IRQ latch.
RST, IRQ: Pins have internal pull up device
All port pins have programmable pull up device
PTA[0:5]: Higher current sink and source capability
PTA0/TCH0/AD0/KBI0
PTA1/TCH1/AD1/KBI1
PTA2/IRQ
/KBI2/TCLK
PTA3/RST
/KBI3
PTA4/OSC2/AD2/KBI4
PTA5/OSC1/AD3/KBI5
4-CHANNEL 16-BIT
TIMER MODULE
KEYBOARD INTERRUPT
MODULE
EXTERNAL INTERRUPT
MODULE
AUTO WAKEUP
LOW-VOLTAGE
INHIBIT
COP
MODULE
10-CHANNEL
10-BIT ADC
ENHANCED SERIAL
PTB0/SCK/AD4
PTB
DDRB
M68HC08 CPU
PTA
DDRA
PTB1/MOSI/AD5
PTB2/MISO/AD6
PTB3/SS
/AD7
PTB4/RxD/AD8
PTB5/TxD/AD9
PTB6/TCH2
PTB7/TCH3
POWER SUPPLY
V
DD
V
SS
CLOCK
GENERATOR
COMMUNICATIONS
INTERFACE MODULE
MODULE
SERIAL PERIPHERAL
INTERFACE
MC68HC908QB8
8192 BYTES
USER FLASH
256 BYTES
USER RAM
MC68HC908QB8
MONITOR ROM
BREAK MODULE
DEVELOPMENT SUPPORT