What is the main difference Bet. 16f877 vs 16f877A

[uludere72]

does it work properly with my ex program which is writen for 16f877 ..!!

[Melanie]

Do I have a crystal ball? Actually yes, there's one next to my monitor, but when I look in it I can see all kinds of things but unfortunately your program isn't one of them!

If you are blinking a LED on PortB, you got no worries...

If you are using any pin that is shared with a Comparator, then just like the Datasheet says... it's not going to work without adding code to disable those comparators first.

[uludere72]

thanks for your kind response
!

[Joann]

I also have the same problem,i have a code compiled for pic16f877
the data,clock pin is on porta pin,when i program it on pic16f877a i did not work.
how would i disable the comparator.

[mister_e]

Comming from the migration sheet...
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=863&stc=1&d=1146485135 ">

[Joann]

The problem is this,i connected as follows to pic16f877a
porta.0 = clock to 74hc
porta.1 = clock to 74hc
porta.2 = clock to 74hc
porta.3 = input..
porta.4 = input..
porta.5 = output..

portb.0 - 7 = outputs.
portc.0 - 7 = outputs.

i have tried to ,cmcon = 7
adcon1 = 7
still is not working .
but the code work on pic16f876.

[mister_e]

Is your programmer support the 16F877a as it can have some programming time difference.

Also, the A serie are bit much noise sensitive, be sure you place the proper psu filtering cap close to your PIC.