Pin Descriptions And Input/Output Ports; Pin Descriptions - Motorola MC68HC05T16 Technical Data Manual

PIN DESCRIPTIONS AND
INPUT/OUTPUT PORTS
This section provides a description of the functional pins and I/O programming of the
MC68HC05T16/ MC68HC705T16 microcontroller.
2.1

PIN DESCRIPTIONS

PIN NAME
VDD, VSS
IRQ/VPP
RESET
TCAP
EXTAL, XTAL
PA0-PA7
PB0-PB7
MC68HC05T16

PIN DESCRIPTIONS AND INPUT/OUTPUT PORTS

2
56-pin SDIP
PIN No.
Power is supplied to the MCU using these two pins. VDD is power and
41, 44
VSS is ground.
In the user mode this pin is an external hardware interrupt IRQ. It is
software programmable to provide two choices of interrupt triggering
sensitivity. These options are:
38 1) negative edge-sensitive triggering only, or
2) both negative edge-sensitive and level sensitive triggering.
In the bootstrap mode on the MC68HC705T16, this is the EPROM
programming voltage input pin.
The active low RESET input is not required for start-up, but can be
53 used to reset the MCU internal state and provide an orderly software
start-up procedure.
The TCAP input controls the input capture feature for the on-chip
15
programmable free-running timer.
These pins provide connections to the on-chip oscillator. The
51, 52 maximum crystal frequency is 4.2 MHz. EXTAL may be driven by an
external oscillator if an external crystal circuit is not used.
These eight I/O lines comprise port A. The state of any pin is software
31-24 programmable. All port A lines are configured as input during power
on or external reset.
These eight I/O lines comprise port B. The state of any pin is software
16-23 programmable. All port B lines are configured as input during power
on or external reset. These pins are +12V open-drain pins.
DESCRIPTION
2
TPG
MOTOROLA
2-1