基于P89LPC915开发的比较器报警教学方案，程序采用单片机内部400KHz振荡器，P0.4、P0.5正反相输入，比较产生中断时，在P0.1输出25KHz的单音报警持续2s。-P89LPC915 based alarm comparator developed teaching programs, procedures using single-chip internal 400KHz oscillator, P0.4, P0.5-phase positive and negative input, compare interrupt generated when the P0.1 output 25KHz continuous tone alarm 2s.