dallas 1线EPROM 12V编程脉冲的I/O保护

系统由USB 5V供电；PIC16F1459是1线主控器，16F1459IO1用于1-线通信；16F1459IOI2被设计为在总线上应用12V（或5V）编程功率；我的问题是：当12V应用于1线时，电路将工作16F1459IO1保护吗？2.当PIC开机或复位（IO2浮动）时，我希望Q3可以快速切断（快于Q1开启时间，抱歉我的英语不好），因此12V不会导致PIC；3.如果2失败，这意味着Q3被切断后比Q1打开，那么PIC的IO端口能忍受多长时间12V？谢谢指教！UZSLM！



      以下为原文

    system is powered by USB 5V;
PIC16F1459 is an 1-wire master,16F1459_IO1 for 1-wire communication;
16F1459_IO2 is designed to apply 12V(or 5V) programming power on the bus;
my question is:
1.will the circuit work for 16F1459_IO1 protection when 12V is applied on the 1-wire?
2.when PIC powering on,or resetting(IO2 floating),i hope the Q3 could cut off quickly(quick than Q1 turn on time,sorry for my poor english),so that 12V will be not led to PIC ;
3.if 2 failed,which mean Q3 cut off later than Q1 turned on,then how long the PIC's IO port could endure the 12V?

Thanks for advice!!
uzslm

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