HC705E5GRSSLASHD datasheet(36/148 Pages) NXP

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Interrupts

General Release Specification

MC68HC705E5 — Rev. 1.0

Interrupts

4.5 External Interrupt

If the I bit of the condition code reister (CCR) is set, all maskable

interrupts (internal and external) are disabled. Clearing the I bit enables

interrupts. The interrupt request is latched immediately following the

falling edge of IRQ. It is then synchronized internally and serviced by the

interrupt service routine located at the address specified by the contents

of $1FFA and $1FFB.

Either a level-sensitive and edge-sensitive trigger or an

edge-sensitive-only trigger is available as a mask option.

NOTE:

The internal interrupt latch is cleared in the first part of the interrupt

service routine; therefore, one external interrupt pulse could be latched

and serviced as soon as the I bit is cleared.

4.6 Timer Interrupt

Two different timer interrupt flags cause a timer interrupt whenever they

are set and enabled. The interrupt flags and enable bits are located in

the timer control and status register (TCSR). Either of these interrupts

will vector to the same interrupt service routine, located at the address

specified by the contents of memory location $1FF8 and $1FF9. For

additional information, refer to 8.3 Timer Control and Status Register.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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