On Fri, Oct 19, 2012 at 5:40 PM, Oliver Seitz <[email protected]> wrote:
>
> Between now and a fix you might experiment with the procedure
> pwm1_set_percent_dutycycle() in stead of the procedures for 'absolute'
> settings.
>
> This is a good hint. And I would like to add: Always set the frequency
> first, and the duty cycle afterwards. Also, if you're changing the
> frequency,
> always set the duty cycle again (in percent).
>
like this:
-- start settings
pwm_max_resolution(1)
pwm_set_frequency
var byte PWMH_duty = 40
pwm1_set_dutycycle_highres(PWMH_duty)
pwm1_off()
-- end settings
where pwm_set_frequency has been modified as follows:
procedure pwm_set_frequency is
const dword freq = 12000
_pr2_shadow_plus1 = word(target_clock / freq) / 4
T2CON = 0b0000_0000 -- zero pre/postscaler,
disable Timer2
if ((_pr2_shadow_plus1 > 0) & -- freq not too high and
(_pr2_shadow_plus1 <= 4096)) then -- freq not too low
if (_pr2_shadow_plus1 <= 256) then
T2CON_T2CKPS = 0b00 -- set Timer2 prescaler 1:1
elsif (_pr2_shadow_plus1 <= 1024) then
_pr2_shadow_plus1 = _pr2_shadow_plus1 / 4
T2CON_T2CKPS = 0b01 -- 1:4
else
_pr2_shadow_plus1 = _pr2_shadow_plus1 / 16
T2CON_T2CKPS = 0b10 -- 1:16
end if
PR2 = byte(_pr2_shadow_plus1 - 1) -- set PR2
T2CON_TMR2ON = TRUE -- enable Timer2
end if
end procedure
Vasile
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