Deciding Reset Source; Figure 17.6 Timing Of Setting Bits In Reset Source Decision Register; Table 17.2 Deciding Reset Source - Renesas H8 Series Hardware Manual

17.3.3

Deciding Reset Source

The source of a reset can be decided by reading the reset source decision register (LVDRF) in the
reset exception handler (see table 17.2). After that, writing 0 to the bit can clear the flag and can
be ready to decide the next reset source.
Figure 17.6 shows a timing of setting the bits in the register.

Table 17.2 Deciding Reset Source

LVDRF
PRST
1
0
0
Power supply voltage
Internal reset signal
PRST bit
WRST bit

Figure 17.6 Timing of Setting Bits in Reset Source Decision Register

Section 17 Band-Gap Circuit, Power-On Reset, and Low-Voltage Detection Circuits
WRST
0
0
1
Set by
power-on reset
Read and
cleared
(0 is written)
Reset Source
Power-on reset or LVDR occurred
Reset signal input on external reset pin
WDT reset occurred
Set by temporary drop of
power supply voltage
Read and
cleared
(0 is written)
Rev. 1.00 Aug. 28, 2006 Page 299 of 400
Set by
WDT reset
Read and
cleared
(0 is written)
REJ09B0268-0100