GENERAL DESCRIPTION
The MC68HC05P4A is a 28-pin device based on the MC68HC05P4. The memory
map includes 4160 bytes of user ROM and 176 bytes of RAM. The MCU has two
8-bit input/output (I/O) ports, A and C. Port B has three I/O pins and port D has
two pins, one that is I/O and the other input only. The MC68HC05P4A includes a
simple serial I/O peripheral (SIOP) and an on-chip mask programmable computer
operating properly (COP) watchdog circuit.

Features
• Low Cost
• HC05 Core
• 28-Pin Package
• On-Chip Oscillator with RC or Crystal/Ceramic Resonator Mask Options
• 4160 Bytes of User ROM Including 16 User Vector Locations
• ROM Security Feature
• 176 Bytes of On-Chip RAM
• 16-Bit Timer
• Edge-Sensitive or Edge- and Level-Sensitive Interrupt Trigger Mask
Option
• Simple Serial Input/Output Port
• Mask Option Selectable Watchdog Timer (COP)