The AVR core 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 ATmega8 provides the following features: 8K bytes of In-System Programmable Flash with Read-While-Write capabilities, 512 bytes of EEPROM, 1K byte of SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible Timer/Counters with compare modes, internal and external interrupts, a serial program- mable USART, a byte oriented Two-wire Serial Interface, a 6-channel ADC (eight channels in TQFP and MLF packages) where four (six) channels have 10-bit accuracy and two channels have 8-bit accuracy, a programmable Watchdog Timer with Internal Oscillator, an SPI serial port, and five 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 Power-down mode saves the register contents but freezes the Oscillator, disabling all other chip functions until the next Interrupt or Hard- ware Reset. In Power-save mode, the asynchronous timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping. The ADC Noise Reduction mode stops the CPU and all I/O modules except asynchronous timer and ADC, to minimize switching noise during ADC conversions. In Standby mode, the crys- tal/resonator Oscillator is running while the rest of the device is sleeping. This allows very fast start-up combined with low-power consumption. The device is manufactured using Atmel’s high density non-volatile memory technology. The Flash Program memory can be reprogrammed In-System through an SPI serial interface, by a conventional non-volatile memory programmer, or by an On-chip boot program running on the AVR core. The boot program can use any interface to download the application program in the Application Flash Memory. Software in the Boot Flash Section will continue to run while the Application Flash Section is updated, providing true Read-While-Write operation. By combining an 8-bit RISC CPU with In-System Self- Programmable Flash on a monolithic chip, the Atmel ATmega8 is a powerful microcon- troller that provides a highly-flexible and cost-effective solution to many embedded control applications. The ATmega8 AVR is supported with a full suite of program and system development tools, including C compilers, macro assemblers, program debugger/simulators, In-Cir- cuit Emulators, and evaluation kits. AVR 内核具有丰富的指令集和 32 个通用工作寄存器。所有的寄存器都直接与算逻单元 (ALU) 相连接,使得一条指令可以在一个时钟周期内同时访问两个独立的寄存器。这种结 构大大提高了代码效率,并且具有比普通的 CISC微控制器最高至 10倍的数据吞吐率。 ATmega8 有如下特点 :8K 字节的系统内可编程 Flash( 具有同时读写的能力,即 RWW), 512 字节 EEPROM,1K 字节 SRAM,32 个通用 I/O 口线,32 个通用工作寄存器,三个 具有比较模式的灵活的定时器 / 计数器 (T/C), 片内 / 外中断,可编程串行 USART,面向 字节的两线串行接口, 10 位 6 路 (8 路为 TQFP 与 MLF 封装 )ADC,具有片内振荡器的 可编程看门狗定时器,一个 SPI 串行端口,以及五种可以通过软件进行选择的省电模式。 工作于空闲模式时 CPU 停止工作,而 SRAM、 T/C、 SPI 端口以及中断系统继续工作; 掉电模式时晶体振荡器停止振荡,所有功能除了中断和硬件复位之外都停止工作;在省 电模式下,异步定时器继续运行,允许用户保持一个时间基准,而其余功能模块处于休眠 状态; ADC 噪声抑制模式时终止 CPU 和除了异步定时器与 ADC 以外所有 I/O 模块的工 作,以降低 ADC 转换时的开关噪声; Standby 模式下只有晶体或谐振振荡器运行,其余 功能模块处于休眠状态,使得器件只消耗极少的电流,同时具有快速启动能力。 本芯片是以 Atmel 高密度非易失性存储器技术生产的。片内 ISP Flash 允许程序存储器通 过 ISP 串行接口,或者通用编程器进行编程,也可以通过运行于 AVR 内核之中的引导程 序进行编程。引导程序可以使用任意接口将应用程序下载到应用Flash存储区(Application Flash Memory)。在更新应用Flash存储区时引导Flash区(Boot Flash Memory)的程序继续 运行,实现了 RWW 操作。 通过将 8 位 RISC CPU 与系统内可编程的 Flash 集成在一个 芯片内,ATmega8 成为一个功能强大的单片机,为许多嵌入式控制应用提供了灵活而低 成本的解决方案。 ATmega8 具有一整套的编程与系统开发工具,包括:C 语言编译器、宏汇编、 程序调试 器 / 软件仿真器、仿真器及评估板。 自己先选一个AVR单片机的型号,然后可以在网上找到其中文和英文datasheet,自己对照稍微改一下,增加几句自己的话就可以简单搞定了,如上面的内容一样