Hi,
I have developed a door control system using a PIC16F877 microcontroller.
It mostly get stuck but sometimes work nicely. I'm quite clear that it is a problem of the microcontroller since I was able to operate the other parts separately.
The oscillator I used is a 40 MHz one and I used Power MOSFET for switching.
Do you have any idea?
Leo
Strange issue in 16F877
Re: Strange issue in 16F877
Hi ,
Can you try with some bit low frequency oscilator like 4 MHz . As your application is not very much speed critical ,
there is no need to go for high frequency oscilator. 4 MHz is very much sufficient for you application.
When you choose an oscilator , you must check the maximum speed , that your microcontroller could clock.
you can see this in the data sheet. if you clock the microcontroller more than this threshold frequency ,
It will not work correctly
Can you try with some bit low frequency oscilator like 4 MHz . As your application is not very much speed critical ,
there is no need to go for high frequency oscilator. 4 MHz is very much sufficient for you application.
When you choose an oscilator , you must check the maximum speed , that your microcontroller could clock.
you can see this in the data sheet. if you clock the microcontroller more than this threshold frequency ,
It will not work correctly
Re: Strange issue in 16F877
16f877 isn't working with 40 MHz oscillators. Max 20 Mhz try data sheet
Re: Strange issue in 16F877
Working with microcontrollers needs bit of reading, planning and proper circuit design, even for a simple project. These devices are extremely susceptible to electrical noise, min/max voltages, signal thresholds, and not least the usage of proper and matching interconnecting devices.
As an example, your project wont need higher clock frequencies to operate in the first place. So going on slower makes life easier. High frequency means more demanding interconnecting devices. Meaning all signals going into external devices at higher frequencies also should be within responsive regions.
All this attributes to reading of the specifications first
As an example, your project wont need higher clock frequencies to operate in the first place. So going on slower makes life easier. High frequency means more demanding interconnecting devices. Meaning all signals going into external devices at higher frequencies also should be within responsive regions.
All this attributes to reading of the specifications first