5 Star

通信接口的编写应尽量

.采用中断+缓冲区，



.分层+结构化设计，



.尽量不使用轮循方式(降低AVR的效率)。参见URAT（RS232）驱动+中间层软件示例。

提高硬件可靠性的考虑:

.尽量采用片内晶体、采用低频率的系统时钟、振荡电路的输出小幅度。



.选择合适的启动延时参数



.使用BOD、片内的看门狗



.合理休眠方式的使用



.不用I/O口设定输出低电平



.利用内部的EEProm和寄存器MCUCSR判断复位标志，进行不同的处理

• procedure definition with inputs and return values;
  
  
• global variables and local procedure inputs;
  
  
• control structures like if, repeat, and
  loop;
  
  
• a 16-bit number system (addition, subtraction, multiplication,
  division, remainder, comparison, bitwise operations, random
  function);
  
  
• motor and sensor primitives;
  
  
• timing functions and tone-playing functions;
  
  
• data recording and playback primitives;
  
  
• communications primitives.

ab, onfor 20

There is also a free-running timer, which keeps track of elapsed
time even when the Cricket is doing other things.

global [cats dogs]

creates two globals, named cats and
dogs. Additionally, two global-setting primitives,
setcats and setdogs, are instantiated.

The infrared protocol includes the following capabilities:

• 
  
  Check that a Cricket is present and ready for other commands.
  
• 
  Write a byte to the Cricket's EEPROM.
  
• 
  Read a byte from the Cricket's memory.
  
• 
  Begin program execution from a particular memory address.

equation:

abs(new_reading - calibrating_reading)/calibrated_reading * 100 = similarity




now using our numbers:


grey floor = (108 - 95)/95 * 100 = 13.7% different


white line = (108 - 112)/112 * 100= 3.6% different




compare: white line < grey floor


therefore the sensor sees a white line

if you wanted three different colors it would look something like this:

There are only 3 steps you need to follow: