Renesas M16C FAMILY Hardware Manual page 84

R8C/18 Group, R8C/19 Group
Table 10.6 Determining Interrupt Source for Oscillation Stop Detection, Watchdog Timer, and
Voltage Monitor 2 Interrupts
Generated Interrupt Source
Oscillation stop detection
((a) or (b))
Watchdog timer
Voltage monitor 2
Figure 10.9 Procedure for Switching Clock Source from Low-Speed On-Chip Oscillator to Main
Clock
Rev.1.30 Apr 14, 2006
REJ09B0222-0130
(a) OCD3 bit in OCD register = 1
(b) Bits OCD1 to OCD0 in OCD register = 11b and OCD2 bit = 1
VW2C3 bit in VW2C register = 1
VW2C2 bit in VW2C register = 1
Switch to main clock
Determine OCD3 bit
0 (main clock oscillates)
Judge several times
Determine several times that the main clock is supplied
Set bits OCD1 to OCD0 to 00b
(oscillation stop detection function
disabled)
Set OCD2 bit to 0
(select main clock)
End
Page 69 of 233
Bit Showing Interrupt Cause
1 (main clock stops)
OCD3 to OCD0: Bits in OCD register
10. Clock Generation Circuit