Pic16F877 & Pic16F877A

[alzomor]

Hi

I made a programme for PIC16F877 .
it's working correctly on Proteus Simulator.
but I found Pic16F877A in the market.
When programed Pic16F877A with the program of Pic16F877 and test it in circuit , it's not working propaply.
My queston is how to modify my work to be workable with PIC16F877A

Salam
Hossam Alzomor

 

[philba]

From your post, I can't tell if you debugged it on a real 877. The 877A and 877 code should be identical. If it worked of a real 877, is should also work on the 877A but a simulator isn't good enough. There are many things that will prevent it from working.

Things to look at:
- read the program back to make sure it actually got programmed
- verify your hardware (+5V, gnd connections, mclr pulled to +5, crystal/caps or resonator)
- if you have an o'scope, check the oscillator pins (osc1 or osc2) with a high impedence probe.
- write a super simple program that toggles 1 pin on and off every second or so and check the output with a dvm or led.

 

[Lykos1986]

What is the different between the normal PIC and the PIC-A devices

 

[philba]

there is no single answer. the 877 and 877A differ in their programming algorithms. This means that you need a different boot loader. Other than that, I believe they are the same. Code that doesn't deal with the flash will work on both. Often the A parts are a die shrink version so they cost less to make and are thus cheaper.

 

[IanP]

PIC16F87X -- > PIC16F87XA Migration
https://ww1.microchip.com/downloads/en/devicedoc/39591a.pdf

Regrads,
IanP