HPWM confusion

[lerameur]

Hi,

I am learning the HPWM command.. mainly because I need a PWM for my motors. But I was wandering what the command ccp1 does in the Pic16f876a chip does. At first I thought I needed it, but then i saw that the Pic16F84 dont have one and it is possible to have PWM, Actually I guess its a question of, what pin is turning on and off at a specific duty cycle. So what is the PWM mode in the pic16F876a with the CCP0, CCP1, What does it give more then the 16F84 chip.

thanks

ken

[mat janssen]

The PWM command in PBP is a software pwm generator. When this command is running nothing else is workin until the pwm genarator is ready, because you give the dutycycle and the number of cycles of this pwm to the genarator.
When the cycles are done then the next command is working.
The HPWM command is a command what goes directly to the hardware buils in pwm generator. When it is started is will work until you give a command to stop or to give it another dutycycle. Meanwhile your programm is doing then next instructions without concirning about the pwmgenerator.

[sayzer]

For CCP1, I also would like to ask a question in addition to lerameur's, as I am also having new experiences with PWM.

1. When setting PR2 and CCP1, say we set CCP1 for a fixed number. Then we play with PR2 to get the correct freq (in brief I say it this way).

2. But, when I set PR2=255 fixed, and then play with CCP1, I also get the same freqs as in number 1 above.


So what should be my question here, I am not sure.


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[Melanie]

>> But I was wandering what the command ccp1 does in the Pic16f876a chip does.

CCP1 is NOT a command, but a REGISTER within your PIC.

To discover what it does, download and read the Datasheet for your PIC16F876A. A really good place to start is section 8 - Capture/Compare/PWM Modules.

[sayzer]

Welcome back Melanie!



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[lerameur]

So grossely, I am doing a line following robot, if I use PWM, then the sensors are not working. Also, I only have two channel to use PWM, so only two motors can use HPWM on one chip. right?

k