Datasheet

Resets and Interrupts
Resets
MC9S12DP256 — Revision 1.1
Resets and Interrupts
Resets
There are four possible sources of reset. Power-on reset (POR), and
external reset on the RESET
pin share the normal reset vector. The
computer operating properly (COP) reset and the clock monitor reset
each has a vector. Entry into reset is asynchronous and does not require
a clock but the MCU cannot sequence out of reset without a system
clock.
Power-On Reset An on-chip Power-On Reset (POR) circuit detects when VDD to the
MCU has reached a certain level and triggers the internal power on reset
sequence.
Figure 11 and Figure 12 show the power-up sequence for cases when
the RESET
pin is tied to VDD and when the RESET pin is held low.
Figure 11 RESET pin tied to VDD (by a pull-up resistor)
VDD
RESET
Internal POR
4096 ECLKs
V
PORR
64 ECLKs
32 ECLKs
Internal RESET
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc...