烧写程序如何加密？

可以自己在外面加分频器啊，如果成本控制不是很严格的话

RAM是否丢失不确定，因为有的SFR也会被清除的。
我做过这个实验：
把wdt打开，但是不clrwdt，让它溢出；同事把ram清除的程序去掉，但是运行的结果还是不理想。
如果发生WDT overtime时，我希望保存的RAM数据也是错误的，那即使保存也没有意义了啊，你认为呢？

每次reset前,儲值進eeprom...？
我们不知道看门狗什么时候复位,那么在什么时候调用写eeprom的程式呢？

2. Programmer選取燒錄器?
ICD2不可以直接烧写HEX嘛？

Product: PIC16F883<br />I use it to design a timer relay to realize a longtime delay, such as 5 hours. 2 hours later, the MCU resets because of the watchdog, for example, it may be caused by EMI. It will run at 0000h again. Although the MCU runs correctly again, because of the reset, the Related RAMs and SFRs have been changed. The delay time will be calculated from zero again. The total delay time will be 7 hours, not 5 hours if the MCU will not reset again. So, this watchdog reset has no sense for this timer relay product. Do you have any methods to store the correct information before reset? And after reset, the delay time will be calculated from 2 hours not zero. Then we will get not 7 hours but 5 hours delay totally. Do we have any chance to realize this function?<br />

Product: PIC16F883
用它做一个长时间定时的时间继电器，比如定时5个小时，当2个小时已经过去了，此时，由于看门狗复位，比如EMI导致的,程序重新从0000h开始运行,那么运行的数据全部丢失了，时间继电器又重新开始计时了。这样的看门狗复位对于时间继电器这种产品没有意义了。有什么方法能够保存复位前的正确信息，可以让看门狗复位之后，得到正确的5小时定时，而不是7小时？有没有可能实现？

Product: PIC16F883

Problem Description:
if overtime reset is caused by watchdog. it is hot-start. do i need to store the RAMs and PCs? after reset, POP them or repleces current RAMs and PCs with the value i have stored?
my boss let me do this,but i think, except i have not clear watchdog correctly, since overtime reset happens, it indicates that something is wrong,caused by such as EMI.
The current RAMs and PCs is absolutely wrong. Restore them may cause "Death cycle" or not? i think it is not a good idea. thank you.

good idea
thank you very much

BANKSEL OPTION_REG；bank1
BSF OPTION_REG,7
CLRF TRISB
BANKSEL PORTB；bank0
CLRF PORTB

"BANKSEL PORTB"

这句不加，一样可以将PORTB清零，有点困惑

我用的是16F883的芯片。
bank的切换是针对SFR还是GPR，还是全部RAM