mc68hc05jp6pe Freescale Semiconductor, Inc, mc68hc05jp6pe Datasheet - Page 28

• Manufacturer Part Number: mc68hc05jp6pe
• Description: M68hc05 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

General Description
1.7.5 Internal Low-Power Oscillator
1.8 RESET Pin
1.9 IRQ Pin
General Release Specification
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An internal low-power oscillator (LPO) is provided which has a nominal
frequency of 100 kHz. This oscillator can be selected via software in
place of the external oscillator which uses external components
connected to the OSC1 and OSC2 pins. When operating from this
internal LPO, the other oscillator can be powered down by software to
further conserve power.
All standard parts, whether 20 pin, 28 pin, RC option, or crystal, have the
nominal frequency of 100 kHz for the LPO. However, a 500-kHz
frequency LPO is available also. Either the 100-kHz or the 500-kHz LPO
is selected by the low-power oscillator mask option.
The RESET pin can be used as an input to reset the MCU to a known
startup state by pulling it to the low state. It also functions as an output
to indicate that an internal COP watchdog, illegal address, or low-voltage
reset has occurred. The RESET pin contains a pullup device to allow the
pin to be left disconnected without an external pullup resistor. The
RESET pin also contains a steering diode that, when the power is
removed, will discharge to V
connected between the RESET pin and V
contains an internal Schmitt trigger to improve its noise immunity as an
input.
The IRQ input pin drives the asynchronous IRQ interrupt function of the
CPU. Using a mask option, the IRQ interrupt function uses either
negative edge-sensitive triggering or both negative edge-sensitive and
low level-sensitive triggering. If level-sensitive triggering is selected, the
IRQ pin requires an external resistor to V
the IRQ pin is not used, it must be tied to the V
contains an internal Schmitt trigger as part of its input to improve noise
immunity. The voltage on this pin may affect the mode of operation if the
General Description
DD
any charge left on an external capacitor
MC68HC05JJ6/MC68HC05JP6
DD
SS
for “wired-OR” operation. If
. The RESET pin also
DD
Freescale Semiconductor
supply. The IRQ pin
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Rev. 3.2