General Description
processor unit (CPU) and are available with a variety of subsystems,
memory sizes and types, and package types.
The MC68HC705C4A is similar to the MC68HC705C8A. The major
differences are that the MC68HC705C4A has less RAM and ROM, no
selectable memory configurations, no clock monitor reset function, and
only one computer operating properly (COP) watchdog timer. The
MC68HSC705C4A, introduced in Appendix A. MC68HSC705C4A, is
an enhanced, high-speed version of the MC68HC705C4A.
1.3 Features
Features of the MC68HC705C4A include:
• M68HC05 central processor unit (CPU)
• On-chip oscillator with crystal/ceramic resonator
• Memory-mapped input/output (I/O)
• Computer operating properly (COP) watchdog timer
• Selectable port B external interrupt capability
• High current drive on pin C7 (PC7)
• 24 bidirectional I/O lines and 7 input-only lines
• Serial communications interface (SCI) system
• Serial peripheral interface (SPI) system
• Bootstrap capability
• Power-saving stop, wait, and data-retention modes
• Single 3.0-volt to 5.5-volt supply (2-volt data-retention mode)
• Fully static operation
• Software-programmable external interrupt sensitivity
NOTE:
A line over a signal name indicates an active low signal. For example,
RESET is active high and RESET is active low. Any reference to voltage,
current, or frequency specified in the following sections will refer to the
nominal values. The exact values and their tolerance or limits are
specified in Section 13. Electrical Specifications.
Technical Data
22
MC68HC705C4A • MC68HSC705C4A — Rev. 3.0
General Description
MOTOROLA