M16C65 Datasheet, PDF (157/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
8. Clock Generator
8.7 Oscillation Stop/Re-Oscillation Detect Function
This function is to detect the stop and re-oscillation of the main clock oscillation circuit. The oscillation
stop and re-oscillation detect function can be enabled and disabled with the CM20 bit in the CM2 register.
A reset or oscillation stop/re-oscillation detection interrupt is generated when an oscillation stop or re-
oscillation is detected. Set the CM27 bit in the CM2 register to select the reset or interrupt.
Table 8.6 lists Specification Overview of Oscillation Stop and Re-Oscillation Detect Function.
Table 8.6 Specification Overview of Oscillation Stop and Re-Oscillation Detect Function
Item
Oscillation stop detectable clock and
frequency bandwidth
f(XIN) ≥ 2 MHz
Specification
Enabling condition for oscillation stop/ Set CM20 bit to 1 (enabled)
re-oscillation detect function
Operation at oscillation stop/
re-oscillation detection
When CM27 bit is 0: Oscillation stop detection reset generated
When CM27 bit is 1: Oscillation stop/re-oscillation detection
interrupt generated
8.7.1 Operation When CM27 Bit is 0 (Oscillation Stop Detection Reset)
When main clock stop is detected while the CM20 bit is 1 (oscillation stop/re-oscillation detection
function enabled), the MCU is initialized, and then stops (oscillation stop reset). (Refer to 4. “Special
Function Registers (SFRs)” and 6. “Resets”.)
The status is cancelled at hardware reset or voltage monitor 0 reset. The MCU can also be initialized
and stopped when re-oscillation is detected, but do not use the MCU in this manner (during main clock
stop, do not set the CM20 bit to 1 and the CM27 bit to 0).
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
Page 122 of 791