mc68hc05bs8 Freescale Semiconductor, Inc, mc68hc05bs8 Datasheet - Page 35

• Manufacturer Part Number: mc68hc05bs8
• Description: Mc68hc05 Family Of Low-cost Single-chip Microcontrollers.
• Manufacturer: Freescale Semiconductor, Inc

The section describes the reset and interrupt functions available on the MC68HC05BS8.
5.1
The MC68HC05BS8 can be reset in four ways:
•
•
•
•
Any of these resets will cause the program to go to its starting address, specified by the contents
of memory locations $3FFE and $3FFF, and cause the interrupt mask (I-bit) of the Condition Code
register to be set.
5.1.1
The power-on reset occurs when a positive transition is detected on the supply voltage, V
power-on reset is used strictly for power-up conditions, and should not be used to detect any drops
in the power supply voltage. There is no provision for a power-down reset. The power-on circuitry
provides for a 4064 t
RESET pin is low at the end of the 4064 t
until RESET goes high. The user must ensure that V
operate properly prior to the time the 4064 POR cycles have elapsed. If there is doubt, the external
RESET pin should remain low until such time that V
specified.
MC68HC05BS8
by the initial power-on reset function, (POR)
by an active low input to the RESET pin, (RESET)
by a COP watchdog timer reset, (COPR)
and by a Low Voltage Reset, (LVR)
RESETS
Power-On Reset (POR)
RESETS AND INTERRUPTS
CYC
delay from the time that the oscillator becomes active. If the external
RESETS AND INTERRUPTS
CYC
time out, the processor remains in the reset condition
5
DD
DD
has risen to the minimum operating voltage
has risen to a point where the MCU can
DD
. The
TPG
5