ON/OFF button for PIC16f877a (ambiguity)

[irilias]

Thank you gentlemen for your replies, much appreciated ..
That's the whole thing that i've attached ( Conditioning Circuit "Amplification + filtering .." and the Command Circuit "Motor + electrovalve .." )
besides the LCD and MMC interfacing circuits ..



i'm still working on the LCD interface with the mcu .. mainly i'm going to wire :

- the "Enable" LCD pin to the pic pin 30 (RD7/PSP7)
- the "Register Select" LCD pin to pic pin 29 (RD6/PSP6)
- the LCD's Data pins (DB0,DB1,DB2, ... DB7) to the pic's (pin 33,pin34,pin35,...pin40) in order (which represent RB0 to RB7)
- and of course Read/Write to the GND & Contrast Adjustment to a Potentiometer

- do you think i should do some changes in any of the circuits ??
- should i add a current limiting resistors or some protection diodes to the ADC0 & ADC1 ?? if so what's the right way to wire the protection diodes into the existing circuit ?

Thank you again for your help ..