INTRODUCTION
The MC68HC05B6 microcomputer (MCU) is a member of Motorola’s MC68HC05 family of low-cost single chip microcomputers. This 8-bit MCU contains an on-chip oscillator, CPU, RAM, ROM, EEPROM, A/D converter, pulse length modulated outputs, I/O, serial communications interface, programmable timer system and watchdog. The fully static design allows operation at frequencies down to dc to further reduce the already low power consumption to a few micro-amps.

FEATUREs
Hardware features
• Fully static design featuring the industry standard M68HC05 family CPU core
• On chip crystal oscillator with divide by 2 or a software selectable divide by 32 option (SLOW mode)
• 2.1 MHz internal operating frequency at 5V; 1.0 MHz at 3V
• High speed version available
• 176 bytes of RAM
• 5936 bytes of user ROM plus 14 bytes of user vectors
• 256 bytes of byte erasable EEPROM with internal charge pump and security bit
• Write/erase protect bit for 224 of the 256 bytes EEPROM
• Self test/bootstrap mode
• Power saving STOP, WAIT and SLOW modes
• Three 8-bit parallel I/O ports and one 8-bit input-only port
• Software option available to output the internal E-clock to port pin PC2
• 16-bit timer with 2 input captures and 2 output compares
• Computer operating properly (COP) watchdog timer
• Serial communications interface system (SCI) with independent transmitter/receiver baud rate selection; receiver wake-up function for use in multi-receiver systems
• 8 channel A/D converter
• 2 pulse length modulation systems which can be used as D/A converters
• One interrupt request input plus 4 on-board hardware interrupt sources
• Available in 52-pin plastic leaded chip carrier (PLCC), 64-pin quad flat pack (QFP) and 56-pin shrink dual in line (SDIP) packages
• Complete development system support available using the MMDS05 development station with the M68HC05B32EM emulation module
• Extended operating temperature range of -40 to +125 °C