Indicator LED connected to DAC

Algorithm development and general DSP issues

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knutolai
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Joined: Wed Nov 23, 2016 9:43 am
Location: Bergen, Norway

Indicator LED connected to DAC

Post by knutolai »

Hey

So I'm writing a program where I use DACR to display a waveshape. Everything is working flawlessly but whenever DACR outputs a value close to 1 or -1 the clip LED lights up. Is this in any way harmful to the chip?

I'm guessing "no", but I always get the vibe that when a clipping indicator for a DSP lights up I'm doing something harmful to the hardware.

-Knut Olai
frank
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Post by frank »

No, nothing bad is happening to the chip in this case, it is just the clip circuit detecting the large values. If it bothers you just lower the max output to below clipping.
Frank Thomson
Experimental Noize
knutolai
Posts: 65
Joined: Wed Nov 23, 2016 9:43 am
Location: Bergen, Norway

Post by knutolai »

Thank you Frank! I'm driving the LED directly with the output from DACR:
DACR -> Resistor -> LED -> Ground

I've read elsewhere on the forum of people using a LED driver solution where DACR connects to the gate of a NPN transistor that switches the LED on or off.

Is there any reasons to not driver the LED directly with the DACR output?
frank
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Post by frank »

The DAC outputs are not designed to drive very much current so it is better to use a buffer with a high impedance which then drives the LED.
Frank Thomson
Experimental Noize
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