The MC68HC908JB8 is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). All MCUs in the family use the enhanced M68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and types, and package types.

特性 Features

Features of the MC68HC908JB8 include:

? High-performance M68HC08 architecture

? Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

? 3-MHz internal bus frequency

? 8,192 bytes of on-chip FLASH memory

? 256 bytes of on-chip random-access memory (RAM)

? FLASH program memory security1

? On-chip programming firmware for use with host PC computer

? Up to 37 general-purpose 3.3V input/output (I/O) pins, including:

– 13 or 10 shared-function I/O pins, depending on package

– 24, 8, or 2 dedicated I/O pins, depending on package

– 8 keyboard interrupts on port A, on all packages

– 10mA sink capability for normal LED on 4 pins

– 25mA sink capability for infrared LED on 2 pins

– 10mA sink capability for PS/2 connection on 2 pins(with USB module disabled)

? 16-bit, 2-channel timer interface module (TIM) with selectable input capture, output compare, PWM capability on each channel, and external clock input option (TCLK)

? Full Universal Serial Bus Specification 1.1 low-speed functions:

– 1.5 Mbps data rate

– On-chip 3.3V regulator

– Endpoint 0 with 8-byte transmit buffer and 8-byte receive buffer

– Endpoint 1 with 8-byte transmit buffer

– Endpoint 2 with 8-byte transmit buffer and 8-byte receive buffer

? System protection features:

– Optional computer operating properly (COP) reset

– Optional low-voltage detection with reset

– Illegal opcode detection with reset

– Illegal address detection with reset

Features of the CPU08 include the following:

? Enhanced HC05 programming model

? Extensive loop control functions

? 16 addressing modes (eight more than the HC0

? 16-bit index register and stack pointer

? Memory-to-memory data transfers

? Fast 8 × 8 multiply instruction

? Fast 16/8 divide instruction

? Binary-coded decimal (BCD) instructions

? Optimization for controller applications

? Efficient C language support