MC68HC05PV8 Datasheet, PDF (31/196 Pages) Freescale Semiconductor, Inc – Techinal Data - rev 1.9

Freescale Semiconductor, Inc.
General Description
Functional Pin Descriptions
1.7 Functional Pin Descriptions
The following paragraphs give a description of the general function for
each pin.
1.7.1 VSUP, VSS and PVSS
The microcontroller is operated from a single power supply. VSUP is
connected to the positive supply, VSS to ground. The on-chip voltage
regulator uses VSUP to derive the VDD supply for the MCU and external
components. PVSS is a separate ground for the relay drivers.
1.7.2 VDD
This pin is driven by the on-chip voltage regulator. It can be used to
provide a regulated voltage to external devices. A capacitor must be
attached to this pin in order to stabilize the regulator.
1.7.3 OSC1, OSC2
The OSC1 and OSC2 pins are the connections for the on-chip oscillator.
A crystal connected across these pins or an external signal connected to
OSC1 provides the oscillator clock. The frequency, f_OSC, of the oscillator
or external clock source is divided by two to produce the internal
operating frequency, f_OP.
1.7.4 RESET
This pin can be used as an input to reset the MCU to a known start-up
state by pulling it to the low state. The RESET pin contains an internal
Schmitt trigger to improve its noise immunity as an input. The RESET pin
has an internal pull-down device that pulls the RESET pin low when
there is an internal COP watchdog reset, power-on reset (POR), illegal
address reset, internal high voltage or an internal low voltage reset.
Refer to Section 5. Resets.
MC68HC(8)05PV8/A — Rev. 1.9
General Description
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Technical Data