r5f71374an80fpv Renesas Electronics Corporation., r5f71374an80fpv Datasheet - Page 98

• Manufacturer Part Number: r5f71374an80fpv
• Description: 32-bit Risc Microcomputer Superh?? Risc Engine Family
• Manufacturer: Renesas Electronics Corporation.

Section 4 Clock Pulse Generator (CPG)
4.7
Function for Detecting Oscillator Stop
This CPG detects a stop in the clock input if any system abnormality halts the clock supply.
When no change has been detected in the EXTAL input for a certain period, the OSCSTOP bit in
OSCCR is set to 1 and this state is retained until a power-on reset is input through the RES pin or
software standby mode is canceled. If the OSCERS bit is set to 1 at this time, an oscillation stop
detection flag signal is output through the WDTOVF pin. In addition, the high-current ports (pins
to which the TIOC3B, TIOC3D, and TIOC4A to TIOC4D signals in the MTU2 and the TIOC3BS,
TIOC3DS, and TIOC4AS to TIOC4DS signals in the MTU2S are assigned) can be placed in high-
impedance state regardless of the PFC setting. For details, refer to appendix A, Pin States.
Even in software standby mode, these pins can be placed in high-impedance state. For details,
refer to appendix A, Pin States. These pins enter the normal state after software standby mode is
canceled. Under an abnormal condition where oscillation stops while the LSI is not in software
standby mode, LSI operations other than the oscillation stop detection function become
unpredictable. In this case, even after oscillation is restarted, LSI operations including the above
high-current pins become unpredictable.
Even while no change is detected in the EXTAL input, the PLL circuit in this LSI continues
oscillating at a frequency range from 100 kHz to 10 MHz (depending on the temperature and
operating voltage).
Rev. 1.00 Sep. 21, 2007 Page 72 of 1124
REJ09B0402-0100