Hello,
We are using the TS-7300 board to control a motor driven with an
H-bride. Therefore, we are using the XDIO-PWM generator to drive the
H-bridge. The problem we have is to set the PWM frequency to 10KHz which
is the maximum switching frequency for this H-Bridge.
If I understand correctly the clock period which is used to generate the
PWM frequency can be set to 26667ns (SLOW) or 13ns (FAST).
Unfortunately both clock periods are not suited for generating a 10 KHz
PWM signal.
- 26667ns period has a too low resolution.
A pwm frequency of 10KHz means a period of 100000ns, with is only 3.7
times the clock period so only a few different dutycycles can be generated.
- 13ns period will overflow the pwm register(s)
The PWM signal is build out of two values, one for the HIGH period and
one for the LOW period, these values are put in the register which has a
maximum value of FFF (4095) for each value.
So this means a maximum period HIGH or LOW of 4095 * 13 = 53235ns.
This value is too low for most duty cycles @10KHZ e.g.
90% duty cycle means 90000ns HIGH.
Since 10KHz is a common PWM-frequency in these kind applications, I must
have overlooked something to generate this frequency properly. E.g. can
the clock period for the PWM counter be set to a multiple of 13ns?
Regards,
Peter.
____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now.
http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|