单片机复位电路的可靠性与抗干扰分析

Reliability and Analysis of Anti-Interference about Reset Circuit of Single Chip Compute

单片机复位电路参数的选定须在振荡稳定后保证复位高电平持续时间大于2个机器周期。电源掉电时复位电路中电容通过二极管迅速放电,待电源恢复正常时实现可靠复位,避免单片机系统在运行中突然掉电或电压跌落而又立即恢复,从而达到抗干扰的作用。在印刷电路板上,单片机复位端口处可并联0.01～0.1μF高频电容,以抑制电源高频噪声干扰或配置施密特电路,以进一步提高对串入噪声的抑制。

The chosen parameter of reset circuit of single chip compute must guarantee that duration of reset high potential could be longer than two machine cycles after stabilization of oscillation. Capacitance discharges rapidly through diode while losing power, and realizes reliable reset when the power returns to normal. In this way, reset circuit prevents the one-chip computer system from suddenly losing power or falling and resuming of the voltage in operation, thus gets the result of anti-interference. On printed circuit board, the reset port could connect a 0.01 ～0.1μF high-frequence capacitance in parallel or dispose Schmitt＇s circuit to suppress the high-frequency noise of power, in order to improve restraint on the coupling noise.