Table 2-3 Sources Of Reset - Fujitsu MB89140 Series Hardware Manual

MAIN/SUBCLOCK
CONTROL BLOCK
Power-on reset
Watchdog timer reset
External reset
Software reset
HARDWARE CONFIGURATION
Reset Control Section
Reset control
Reset
There are four types of resets as shown in Table 2-3.

Table 2-3 Sources of Reset

Reset name
Power-on reset
Watchdog reset
External-pin reset
Software reset
When the power-on reset and reset during the stop state are used, the os-
cillation stabilization time is needed after the oscillator operates. The time-
base timer or watch prescaler controls this stabilization time. Consequently,
the operation does not start immediately even after canceling the reset.
However if Power-on Reset Disabled is selected by the mask option, no os-
cillation stabilization time is required in any state after external pins have
been released from the reset.
Note: If the Power-on Reset unavailable option is selected, keep the RST
pin Low until the oscillation stabilization time selected in the option
has elapsed after power-on.
2-20
Internal reset signal
Description
Turns power on
Overflows watchdog timer
Sets external-reset pin to Low
Writes 0 at RST (bit 4) of STBC