Anyone used to get SSDM UM fading smoothly?

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Anyone used to get SSDM UM fading smoothly?

Postby JIRK » Thu Sep 16, 2010 10:05 pm

Hi all,
I'm working for some time now on UM SSDM wih CY8CLED02. I can get it to work, but the result is that it's fading not very smoothly. Before, I used PWM with 12Bit and 300 Hz refresh. But I got a noisy inductor. So I tried to use SSDM. In fact, the inductor is silent now, but the transition from 0% to 100% I can not drive smoothly. For example, if I program the transition to fade in 5 seconds, then it starts for 2 seconds, light is getting brighter and brighter, then stops increasing brightness for something less than a second, continues increasing brightness for 2 or 3 seconds, stops again increasing brightness, continues to reach 100%. It's something like a "wave" in light output. But if I step the brightness by hand, for example with a switch, I can increase and decrease brightness seamless. Keep bushing the button, give the same result of a "wave" in light output. Can anybody give me a hint?
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Re: Anyone used to get SSDM UM fading smoothly?

Postby Jerson » Fri Sep 17, 2010 5:02 am

I am not sure if my reply will be helpful at all. I have used the SSDM with CY8CLED04 in static mode. I haven't tried the ramp up or down yet. From your description, it appears to me that the interrupts are not being serviced on time or there is some contention between various interrupts that the system is using. That can cause the behaviour your describe.
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