68HC705SP7 datasheet(150/230 Pages) FREESCALE

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Core Timer

General Release Specification

MC68HC705JJ7/MC68HC705JP7 — Rev. 3.0

Core Timer

RTIE — Real-Time Interrupt Enable

This read/write bit enables real-time interrupts. Reset clears RTIE.

1 = Real-time interrupts enabled

0 = Real-time interrupts disabled

CTOFR — Core Timer Overflow Flag Reset

Writing a logic one to this write-only bit clears the CTOF bit. CTOFR

always reads as a logic zero. Reset does not affect CTOFR.

1 = Clear CTOF flag bit

0 = No effect on CTOF flag bit

RTIFR — Real-Time Interrupt Flag Reset

Writing a logic one to this write-only bit clears the RTIF bit. RTIFR

always reads as a logic zero. Reset does not affect RTIFR.

1 = Clear RTIF flag bit

0 = No effect on RTIF flag bit

RT1 and RT0 — Real-Time Interrupt Select Bits 1 and 0

These read/write bits select one of four real-time interrupt rates, as

shown in Table 10-1. Because the selected RTI output drives the

COP watchdog, changing the real -time interrupt rate also changes

the counting rate of the COP watchdog. Reset sets RT1 and RT0,

selecting the longest COP timeout period and longest real-time

interrupt period.

NOTE:

Changing RT1 and RT0 when a COP timeout is imminent or uncertain

may cause a real-time interrupt request to be missed or an additional

real-time interrupt request to be generated. Clear the COP timer just

before changing RT1 and RT0.

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68HC705SP7 датащи(PDF) 150 Page - Freescale Semiconductor, Inc