最近很多杂志介绍了TM3550NL或LM8560集成电路。笔者经使用后摸索出了让其增加秒显示、秒校零和累积计时的三种功能。先把[23]脚接地,再将[19]脚碰一下地即出现秒显示,其分显示的末位移到了原小时显示的末位,秒显示则在原来分显示位置。若再将[21]脚接地,则停止计时(不清零)。这样就完成了累积计时。把[22]脚接地 Many magazines recently introduced the TM3550NL or LM8560 integrated circuits. After using the author to explore out to increase the seconds to show that the second zero and cumulative timing of the three functions. First [23] feet grounded, and then [19] foot touch appears second display, the end of the sub-display moved to the last hour of the last display, second display in the original sub-display position. If [21] feet then grounded, then stop timing (not clear). This completes the cumulative timing. Ground [22] foot