Pic 16f877A MCLR/vpp port

[Maged Ahmad]

Hello,

i'm new to embedded systems and i started to self-learn PIC micro controllers

and i have a question :

Pin 1 from pic 16877A called MCLR/VPP as shown in the following picture
http://t0.gstatic.com/images?q=tbn:ANd9GcS49J_O__Kz2dKG71Y-FduzPUHJBgybBjawV-O6DxbELiZsUi2A

I read before that keeping this port in high state prevents accidental resets to the micro-controller because when this pin is at 0v the microcontroller resets
and so keeping it in high state prevents reseting

But according to this link
**broken link removed**
VPP reset at low state
but at high state it starts at 1st line everytime !

isn't starting at first line is the meaning of reseting ??

 

[Ian Rogers]

Both statements say the same... A reset occurs when MCLR is pulled low... The PIC runs when its kept high.

VPP is the 12+ volts required for programming.

Actually the pic resets at the highest address then rolls to 0... Most of the locations at power up are all set. So the PC on a pic14 will be at b'1111 1111 1111'

Then it rolls over to 0 where the reset vector is...