| View previous topic :: View next topic |
| Author |
Message |
thomas1234
Joined: 27 Oct 2014
Posts: 1
|
| stupid problem with pwm |
 Posted: Mon Oct 27, 2014 12:35 pm |
 |
|
I face a stupid problem with pwm.
I need to have a pwm. This pwm need to be activate if a switch is on and deactivate when switch is off.
i used the following code, but something is going wrong:
| Code: |
while(PIN_B5)
{
setup_compare(PIN_B14, COMPARE_PWM | COMPARE_TIMER2);
set_pwm_duty(PIN_B14,10);
}
|
what is the problem ?
i use PCD compiler v4.09 |
|
 |
asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
|
|
| Posted: Mon Oct 27, 2014 1:43 pm |
|
|
* you never setup or initialized timer2
* never setup the pwm
* you use wrong syntax in set_pwm duty
* v 4.09 is a dodgy old, muchly pirated version of the compiler
UPDATE compiler, and read the manual.
then you might be in better shape |
|
|
temtronic
Joined: 01 Jul 2010
Posts: 9589
Location: Greensville,Ontario
|
|
| Posted: Mon Oct 27, 2014 2:13 pm |
|
|
and of course the obvious
does a 1Hz LED program work ??
jay |
|
|
Jim90
Joined: 27 Apr 2013
Posts: 55
|
| stupid problem with pwm |
| Posted: Wed Nov 05, 2014 11:29 am |
|
|
Actually the problem appear also to compiler 5.007
for example by using the example EX_PWM_PCD.C
| Code: | void main(void)
{
int value=10;
setup_timer2(TMR_INTERNAL | TMR_DIV_BY_1, 0xFFC0);
setup_compare(1, COMPARE_PWM|COMPARE_TIMER2);
set_pwm_duty(1,value * (unsigned int16)64);
}
|
i receive the error message:
Invalid parameters to build in function ::Invalid Pin
at the line:
| Code: | | setup_compare(1, COMPARE_PWM|COMPARE_TIMER2); |
I think that the problem is coming from the header file of the dspic33fj128GP802.h
beacuse for the dspic30F2010 everything is working fine. |
|
|
temtronic
Joined: 01 Jul 2010
Posts: 9589
Location: Greensville,Ontario
|
|
| Posted: Wed Nov 05, 2014 12:04 pm |
|
|
| hmm.. the OP hasn't said which PIC he's using..... |
|
|
Ttelmah
Joined: 11 Mar 2010
Posts: 19967
|
|
| Posted: Thu Nov 06, 2014 1:18 am |
|
|
The answer is simple.
Nothing to do with the processor include file.
All to do with the data sheet, and the capabilities of the processor.
Does this PIC have a fixed OC1 pin for the compare function to use?.
Answer. No.
_You_ have to tell the compiler which of the relocatable peripheral pins you want to use for the peripheral, _before_ you try to use it.
The compiler is telling you what is wrong in it's error message 'Invalid pin' is pretty obvious. |
|
|
Jim90
Joined: 27 Apr 2013
Posts: 55
|
| stupid problem with pwm |
| Posted: Thu Nov 06, 2014 8:16 am |
|
|
this is not the case for me.
The problem appear at the line
| Code: |
setup_compare(1, COMPARE_PWM|COMPARE_TIMER2);
|
timer2,compare pwm,compare timer2 is provided by the microcontroller.
what is going wrong? |
|
|
Ttelmah
Joined: 11 Mar 2010
Posts: 19967
|
|
| Posted: Thu Nov 06, 2014 8:22 am |
|
|
It is the answer for you.
You are trying to use setup_compare, which uses the OC1 pin.
On chips with relocatable peripherals, you _have_ to tell the compiler which pin(s) to use, before using functions that use the peripherals.
Hence it is telling you that it doesn't have a valid pin setup for this function. |
|
|
dyeatman
Joined: 06 Sep 2003
Posts: 1968
Location: Norman, OK
|
|
| Posted: Thu Nov 06, 2014 2:04 pm |
|
|
Search this forum for the term pin_select for a number of examples.
Also see ex_pinselect and ex_pinselect2 in the examples folder.
_________________
Google and Forum Search are some of your best tools!!!! |
|
|
Ttelmah
Joined: 11 Mar 2010
Posts: 19967
|
|
| Posted: Fri Nov 07, 2014 2:22 am |
|
|
As a further comment, you don't want to be continuously sitting in a loop re-configuring the peripheral. It only needs to be setup _once_ unless you are changing things.
So something like:
| Code: |
if (input(PIN_B5))
{
setup_compare(1, COMPARE_PWM | COMPARE_TIMER2);
set_pwm_duty(1,10);
while (input(PIN_B5)) ; //wait for pin to release
set_pwm_duty(1,0); //turn off PWM
}
|
The first parameter in the compare function is the PWM unit number, _not_ a pin number. |
|
|
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
