2010/8/24 vasile surducan <[email protected]>
> So the frequency is a dword counted in hertz?
Yes
> Meaning if we need 29KHz we do pwm_set_frequency (29_000) ?
>
Yes
> It doesn't work for me even with prescaler 1 at 40Mhz and PR2 register
> =0xFF it should work up to 39KHz
>
But did you manually set prescaler and PR2 register ? By "not working", do
you mean the resulting frequency isn't 29KHz ?
>
> The second problem (and is quite a problem) is the length of a small code:
>
> pwm_max_resolution(1)
> pwm_set_frequency(29000)
> pwm1_set_dutycycle_highres(512)
> pwm1_on()
>
> is eating around 800 bytes...
>
Yes, this is called "beauty" :)
I guess dword is killing some bytes while computing frequency parameters
(have you tried to dig this in order to know where bytes are eaten ?). I
guess another procedure where frequency is a constant (assuming you don't
need variable frequency) could be added:
const dword PWM_FREQUENCY = 29_000
include pwm_hardware
...
pwm_max_resolution(1)
-- pwm_set_frequency(29000) ; not needed anymore
pwm1_set_dutycycle_highres(512)
pwm1_on()
Somewhere in pwm libs:
if defined(PWM_FREQUENCY) then
-- user (probably Vasile) needs a constant frequency)
-- => setup freq params as in pwm_set_frequency but this time using
-- a constant.
end if
Cheers,
Seb
>
> Vasile
>
>
> On Mon, Aug 23, 2010 at 1:02 PM, Sebastien Lelong <
> [email protected]> wrote:
>
>> Hi Vasile,
>>
>> Maybe "pwm_set_frequency(dword in freq)", in pwm_common.jal ?
>> See:
>> http://justanotherlanguage.org/content/jallib/tutorials/tutorial_pwm2
>>
>> Cheers,
>> Seb
>>
>> 2010/8/23 vasile surducan <[email protected]>
>>
>>> Hi all,
>>>
>>> In the current pwm library (pwm_common.jal, pwm_hardware.jal,
>>> pwm_ccpx.jal) the pwm frequency can be set exactly (in terms of KHz) ?
>>>
>>> thx,
>>> Vasile
>>>
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>>
>>
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