M16C6NK Datasheet, PDF (362/404 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

Under development
This document is under development and its contents are subject to change.
M16C/6N Group (M16C/6NK, M16C/6NM)
23. Usage Precaution
23.6 Oscillation Stop, Re-oscillation Detection Function
If the following conditions are all met, the following restriction occur in operation of oscillation stop,
re-oscillation stop detection interrupt.
Conditions
• CM20 bit in CM2 register =1 (oscillation stop, re-oscillation stop detection function enabled)
• CM27 bit in CM2 register =1 (oscillation stop, re-oscillation stop detection interrupt)
• CM02 bit in CM0 register =0 (do not stop peripheral function clock in wait mode)
• Enter wait mode from high-speed or middle-speed mode
Restriction
If the oscillation of XIN stops during wait mode, the oscillation stop, re-oscillation stop detection interrupt
request is generated after the microcomputer is moved out of wait mode, without starting immediately.
Figures 23.1 and 23.2 show the operation timing at oscillation stop, re-oscillation stop detection.
XIN
fRING ⁽¹⁾
INT0 input
CPU
operation
Wait mode
Oscillation stop, re-oscillation
detection interrupt request
INT0 interrupt request
XIN stops
Wait mode is released
NOTE:
1. This clock is generated by the on-chip oscillator. It is not supplies after reset.
The operating clock can changes from on-chip oscillator clock (on-chip oscillation oscillating) to BCLK
by using oscicllation stop, re-oscillation detection function or setting the CM21 bit in the CM2 register.
Figure 23.1 Operation Timing at Oscillation Stop, Re-o_{__}s_{__}c_{__}i_{_}l_{_}lation Stop Detection at Wait Mode
(when moving out of wait mode by using INT0 interrupt)
XIN
fRING ⁽¹⁾
CPU
Normal processing
operation
Oscillation stop, re-oscillation
detection interrupt request
Normal processing
XIN stops
NOTE:
1. This clock is generated by the on-chip oscillator. It is not supplies after reset.
The operating clock can changes from on-chip oscillator clock (on-chip oscillation oscillating) to BCLK
by using oscicllation stop, re-oscillation detection function or setting the CM21 bit in the CM2 register.
Figure 23.2 Operation Timing at Oscillation Stop, Re-oscillation Stop Detection at Normal Processing
Rev.2.00 Nov 28, 2005 page 344 of 378
REJ09B0124-0200