初学单片机的一个实例运用，以at89c2051为例，用c语言编写的时钟程序。程序采用了两级中断，具有时钟及秒表功能。-beginners MCU use an example to at89c2051 example, the language used c clock procedures. Adoption of the two suspended, with the clock and stopwatch functions.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001649s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.091952s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.000977s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001142s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.000974s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003187s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000898s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003885s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.016065s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001259s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 322290 [ RunTime:0.018772s ]
