ATMEGA103单片机解密实例解析

   关于ATMEGA103单片机：

　　The ATmega603/103 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 ATmega603/103 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.The AVR core is based on an enhanced RISC architecture that combines a rich instruction set with 32 general purpose working registers. All the 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 ATmega603/103 provides the following features:64K/128K bytes of In-system Programmable Flash, 2K/4K bytes EEPROM, 4K bytes SRAM, 32 general purpose I/O lines, 8 Input lines, 8 Output lines, 32 general purpose working registers, 4 flexible timer/counters with compare modes and PWM, UART, programmable Watchdog Timer with internal oscillator, an SPI serial port and three software selectable power saving modes. The Idle Mode stops the CPU while allowing the SRAM, timer/counters, SPI port and interrupt system to continue functioning. The PowerDown mode saves the register contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. In Power Save mode, the timer oscillator continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping.The device is manufactured using Atmel’s high-density non-volatile memory technology. The on-chip ISP Flash allows the program memory to be reprogrammed in-system through a serial interface or by a conventional nonvolatile memory programmer. By combining an 8-bit RISC CPU with a large array of ISP Flash on a monolithic chip, the Atmel ATmega603/103 is a powerful microcontroller that provides a highly flexible and cost effective solution to many embedded control applications.The ATmega603/103 AVR is supported with a full suite of program and system development tools including: C compilers,macro assemblers, program debugger/simulators,in-circuit emulators, and evaluation kits.