PIC16F877 Microcontroller

[cyeokpeng]

Hi,

One of my projects requires my team to build a remote-controlled boat. One of the features of the boat is an indicator light feature which will blink on and off to indicate that there is this ship nearby and signal to other ships to clear away during dim light conditions (for example visibility is poor due to fog or at night). OK, now is a simple simple question.

Can I use one of the ports (for example port RC0 of the PIC16F877) to output an oscillator output signal of a fixed frequency (the frequency, how to determine or control this frequency in the microcontroller? Is it dependent on the external crystal oscillator clock frequency?) since this port is designated as a Timer1 oscillator output?
How does the oscillator signal output of this port look like if I program the microcontroller to output the desired frequency I want? Is it a square wave signal with logic one at 5V say, and logic 0 at 0 V? If the signal is exactly as above, then I think the LED will blink on/off which satisfy our design specifications.
Another question on the LED, does LEDs have a frequency sensitivity that at a certain threshold frequency, it cannot change fast enough to blink on/off? Or is this limitation of the frequency dependent on how our eyes perceive it, not on the LED itself?

 

[Davorak]

Usually the microcontroller executes instructions slower then the input oscillator frequency. You can look in the documentation for this or just set a port to alternate between +5 and ground and use an oscilloscope to measure the frequency at which it switches.

Another question on the LED, does LEDs have a frequency sensitivity that at a certain threshold frequency, it cannot change fast enough to blink on/off? Or is this limitation of the frequency dependent on how our eyes perceive it, not on the LED itself?

The led can turn off and on faster then our eyes can perceive. The LED does have a limit but that limit is far beyond the perception rate of human eyes.

 

[ravenprp]

Hello,

Yes, you can use port RC0 of the PIC16F877 microcontroller to output an oscillator signal of a fixed frequency. The frequency of the output signal can be controlled by the microcontroller through the Timer1 module. The frequency is dependent on the external crystal oscillator clock frequency, which can be determined by the user during the design process. The output signal of this port will be a square wave with a logic high of 5V and a logic low of 0V, which can be used to drive an LED for blinking on and off.

In terms of frequency sensitivity, LEDs have a specific range of frequencies that they can handle, and if the frequency is too high, the LED may not be able to turn on and off fast enough to produce a visible blinking effect. However, this limitation is usually dependent on the specific LED being used and can vary. Our eyes also have a threshold for perceiving blinking lights, so the frequency should be within a certain range to be noticeable to humans. It is best to test the frequency with the specific LED being used to ensure it meets the design specifications.