PWM, step by step while configuring the SFR

[PA3040]

Dear BigDog and ckshivaram thanks for reply

Let's say I want to ON one LED it's maximum bright and then gradually reduce it finally off
Can you explain using this example what is mean 10bit resolution

 

[ckshivaram]

this gives you circuit and code to control led brightness using pwm..
Lab 9: Pulse Width Modulation (PWM) using PIC CCP module :Embedded Lab

---------- Post added at 17:27 ---------- Previous post was at 17:24 ----------

check this too
**broken link removed**
PWM Intro - Pulse Width Modulation

 

[Tahmid]

You can think of it in 2 ways:

1) The duty cycle register is a 10-bit integer value that determines the duty cycle. CCPR1L contains the more significant 8 bits and CCP1CON<5:4> contain the 2 LSBs.
or
2) The duty cycle register is a 10-bit value with 8-bit integer and 2-bit decimal places.
So, you can think of CCPR1L storing the 8-bit integer value and CCP1CON<5:4> as the 2 decimal places.

Using the 2nd point:
The value of CCPR1L is to be between 0 and 255. DC1B1 and DC1B0 set the decimal places. Here's the setting:

DC1B1 = 0, DC1B0 = 0, Decimal point value = 0
DC1B1 = 0, DC1B0 = 1, Decimal point value = 0.25
DC1B1 = 1, DC1B0 = 0, Decimal point value = 0.5
DC1B1 = 1, DC1B0 = 1, Decimal point value = 0.75

So, if you set PR2 to 255, using CCPR1L = 127 and DC1B1 = 1, DC1B0 = 0, gives you exactly 127.5 for duty cycle control (50%).

If you compare and use this method, you will see that this is more or less the same thing as what bigdogguru has explained. However, I use this method, because, when coding, I like to keep it in my head that the value of the register representing the duty cycle has to be less than PR2 and a percentage of PR2, proportional to the duty cycle.

Bigdogguru has explained the first point here:
https://www.edaboard.com/threads/215581/#post930008

You can go to this page to read through previous discussions on this:
https://www.edaboard.com/threads/215581/

Hope this helps.
Tahmid.

 

[PA3040]

Mr:ckshivaram
Can I have some idea on this
I red gooligum tutorials and found timer0 that include watch crystal 32768 kHz
I know that this is 2 to the power15 but can anybody explain what important of this specific value so we can use another value like 65536 kHz

---------- Post added at 23:37 ---------- Previous post was at 23:01 ----------

ckshivaram
Can I have sample assembly codes using PWM for LED brightness change

 

[Tahmid]

Take a look here:
**broken link removed**
**broken link removed**

Hope this helps.
Tahmid.

 

[PA3040]

Dear All
Can I have some idea on this
I red gooligum tutorials and found timer0 that include watch crystal 32768 kHz
I know that this is 2 to the power15 but can anybody explain what important of this specific value so we can use another value like 65536 kHz