Reset and Boot Entrance
There could be five conditions will cause the device to be reset.
Power-Up
RST pin press
Watch Dog Timer overflows
Power supply drops (option reset)
Software invokes
On the power-up moment, the device will load the NVM bit
HWBS
(OR0.3) into a bit
named
SWBS
in SFR
ISPCR
(explained later), and then determine the boot entrance
according to
SWBS.
If a reset is caused exclusive Power-Up, the boot entrance is determined only by SWBS
while no preloading happens from
HWBS
to
SWBS.
The RST pin is used to reset this device. It is connected into the device to a Schmitt
Trigger buffer to get excellent noise immunity.
Any positive pulse from RST pin must be kept at least 10us plus 36 oscillation cycles, or
the device cannot be reset.
MEGAWIN
MPC82x52A Data Sheet
59
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
