GENERAL DESCRIPTION
The MC68HC05SR3 HCMOS microcontroller is a member of the M68HC05 family of low-cost single-chip microcontrollers. This 8-bit microcontroller unit (MCU) contains on-chip oscillator, CPU, RAM, ROM, I/O, Timer, and Analog-to-Digital Converter. The MC68HC05SR3 is pin compatible with the MC6805R3 and is provided as a low power upgrade path for MC6805R3 applications. The low power advantage of CMOS is combined with the addition of I/O and port modifications which help eliminate external components in cost sensitive applications.

Features
• Fully static chip design featuring the industry standard 8-bit M68HC05 core
• Pin compatible with the MC6805R3
• Power saving STOP, WAIT, and SLOW modes
• 3840 bytes of user ROM with security feature in MC68HC05SR3 3840 bytes of EPROM with security bit in MC68HC705SR3
• 192 bytes of RAM (64 bytes for stack)
• 32 bidirectional I/O lines
• Keyboard interrupts
• 8-bit count-down timer with programmable 7-bit prescaler
• On-chip crystal oscillator, with built-in capacitor for RC option
• Second software programmable external interrupt line (IRQ2)
• Direct LED drive capability on all ports
• Programmable 20KΩ pull-up resistors integrated into I/O ports
• Internal 100KΩ pull-up resistors on IRQ and RESET pins
• Four channel 8-bit Analog to Digital Converter
• Low Voltage Reset
• Available in 40-pin PDIP, 42-pin SDIP and 44-pin QFP packages