双数码管可调秒表 由于单片机I/O资源足够，所以双数码管可接成静态显示方式，两个共阴数码管分别接在P1（秒十位）和P2（秒个位）口，它们的共阴极都接地，安排两个按键接在P3.2（十位数调整）和P3.3（个位数调整）上，为了方便计时，选用12MHz的晶体。为了达到精确计时，选用定时器方式2，每计数250重载一次，即250us，定义一整数变量计数重载次数，这样计数4000次即为一秒。定义两个字节变量S10和S1分别计算秒十位和秒个位。-Double digital tube adjustable stopwatch because single chip I/O adequate resources, so double digital tube may meet into static showing the way, two were Yin digital tube up in respectively P1 (ten seconds) and P2 (seconds bytes) mouth, they were all of the cathode grounding, arrange two buttons up in P3.2 (ten digits adjust) and P3.3 (single digits adjust), in order to facilitate the timing, choose 12 MHz crystals. In order to achieve precise timing, choose the timer way 2, each count 250 overloaded once, namely 250 us, define a variable number of heavy integer count, so that count 4000 times which is a one seconds. Define two bytes variable S10 and S1 separately calculated the ten seconds and seconds bytes.