The AT90CAN32/64/128 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle， the AT90CAN32/64/128 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. The AVR core combines a rich instruction set with 32 general purpose working registers. All 32 registers are directly connected to the Arithmetic Logic Unit （ALU）， allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers. The AT90CAN32/64/128 provides the following features： 32K/64K/128K bytes of In-System Programmable Flash with Read-While-Write capabilities， 1K/2K/4K bytes EEPROM， 2K/4K/4K bytes SRAM， 53 general purpose I/O lines， 32 general purpose working registers， a CAN controller， Real Time Counter （RTC）， four flexible Timer/Counters with compare modes and PWM， 2 USARTs， a byte oriented Two-wire Serial Interface， an 8-channel 10-bit ADC with optional differential input stage with programmable gain， a programmable Watchdog Timer with Internal Oscillator， an SPI serial port， IEEE std. 1149.1 compliant JTAG test interface， also used for accessing the On-chip Debug system and programming and five software selectable power saving modes..