MC68HC705X32CFU Freescale Semiconductor, MC68HC705X32CFU Datasheet - Page 35

• Manufacturer Part Number: MC68HC705X32CFU
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC705X32CFU

• Cpu Family: HC05
• Device Core Size: 8b
• Frequency (max): 4MHz
• Interface Type: SCI
• Program Memory Type: EPROM
• Program Memory Size: 32KB
• Total Internal Ram Size: 528Byte
• # I/os (max): 32
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• On-chip Adc: 8-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: PQFP
• Lead Free Status / Rohs Status: Supplier Unconfirmed

2.3
2.3.1
Power is supplied to the microcontroller using these two pins. VDD is the positive supply and VSS
is ground.
It is in the nature of CMOS designs that very fast signal transitions occur on the MCU pins. These
short rise and fall times place very high short-duration current demands on the power supply. To
prevent noise problems, special care must be taken to provide good power supply bypassing at
the MCU. Bypass capacitors should have good high-frequency characteristics and be as close to
the MCU as possible. Bypassing requirements vary, depending on how heavily the MCU pins are
loaded.
2.3.2
This is an input-only pin for external interrupt sources. Interrupt triggering is selected using the
INTP and INTN bits in the miscellaneous register, to be one of four options detailed in
In addition, the external interrupt facility (IRQ) can be disabled using the INTE bit in the
Miscellaneous register (see
the miscellaneous register while the I-bit is set. Selecting a different interrupt option will
automatically clear any pending interrupts. Further details of the external interrupt procedure can
be found in
The IRQ pin contains an internal Schmitt trigger as part of its input to improve noise immunity. A
high voltage detector is provided on this pin to select modes of operation other than single-chip
mode. See
2.3.3
This active low I/O pin is used to reset the MCU. Applying a logic zero to this pin forces the device
to a known start-up state. An external RC-circuit can be connected to this pin to generate a
power-on reset (POR) if required. In this case, the time constant must be great enough (at least
100ms) to allow the oscillator circuit to stabilise. This input has an internal Schmitt trigger to
improve noise immunity. When a reset condition occurs internally, i.e. from the COP watchdog, the
RESET pin provides an active-low open drain output signal that may be used to reset external
hardware.
MC68HC05X16
Section
Section
Pin descriptions
VDD and VSS
RESET
IRQ
Freescale Semiconductor, Inc.
2.1.
10.2.3.2.
For More Information On This Product,
MODES OF OPERATION AND PIN DESCRIPTIONS
Section
Go to: www.freescale.com
3.8). It is only possible to change the interrupt option bits in
Table
10-3.
2-11
2