Reset pin of PIC

[Rajinder]

Hi,
I have a reset pin of a PIC micro connected to 5V via a 10K pull up resistor.
If i connect a I/O line of a second PIC to the reset of the first PIC. Can i reset the PIC by outputting a zero? Or should it be a logic 1?
Thanks

 

[hexreader]

Zero to reset, 1 to run.

 

[Rajinder]

Thanks.
I wanted to ask what actually happens internally to the MCLR line of the PIC i.e. in terms of the FET/transistors.
Is there any good sources to explain this?
Thanks in advance.

 

[Harald Kapp]

I wanted to ask what actually happens internally to the MCLR line of the PIC i.e. in terms of the FET/transistors.

The rest pin can be considered as a standard input pin which is connected to the reset inputs of all internal logic functions of the mcu.
You should be familiar with the operation of CMOS logic gates. If not, read e.g. here.

 

[Rajinder]

Hi
So am i correct in saying that the pull up is tied to VDD via an PMOS FET internally? A logic 1 will keep the MCLR high. A logic 0 will turn on the PMOS FET and short drain to source to 0V.
Is that correct?

 

[Harald Kapp]

A logic 0 will turn on the PMOS FET and short drain to source to 0V.

No. How should the MOSFET do that when tied to Vcc, not GND?

Read here.

 

[Rajinder]

Hi
Thanks for this. So i would need a switch i.e..FET or similar to bring the MCLR to 0V?

 

[Harald Kapp]

So i would need a switch i.e..FET or similar to bring the MCLR to 0V?

Do you really have to ask this? Isn't it obvious?