M16C Datasheet, PDF (49/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Mitsubishi microcomputers
Specifications in this manual are tentative and subject to change.
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Oscillation Stop Detection Function
Oscillation stop detection register (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
CM2
Address
000C16
When reset
0016
Bit symbol
Bit name
Function
RW
CM20
Oscillation stop
detection bit
0: The function is invalid.
1: The function is valid.
CM21
Main clock switch bit
0: Select Xin (Ring oscillator is stopped.)
1: Select ring oscillator.
CM22
Oscillation stop
0: No meaning
detection status (Note 2) 1: An oscillation stop is detected.
CM23
Clock monitor bit (Note 3)
0: Xin is in operation.
1: Xin is stopped.
CM24
Reserved bit
Always set to "0"
CM25
CM26
CM27
Operation select bit
(when an oscillation stop
is detected)
0: Internal reset on stop detectio
1: Start ring oscillator
Note 1: Set bit 0 of the protect register (address 000A16) to "1" before writing to this register.
Note 2: This bit is valid only in an execution program for the oscillation stop detection inter-
rupt. Use this bit for the purpose of cause judgment(oscillation stop detection- or
watchdog timer interrupt) for interrupt execution. You can write in this bit "0" only.
Note 3: This bit is valid only in an execution program for the oscillation stop detection inter-
rupt. Use this bit for the purpose of confirming Xin operation for interrupt execution.
Figure 5-9. Structure of the oscillation stop detection register
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