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Altera_Forum
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7 years ago

Driving Ladder DAC

Hi, Im trying to drive a resistor ladder DAC from my DE-1 SOC board, despite of my DAC being very accurate im getting somewhat shotty results. The setup is relatively simple driving the resis...
Altera_Forum's avatar
Altera_Forum
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7 years ago

It shoud look like the 3rd picture in the first series, A somewhat shotty sawtooth wave.

I cant do much "Warning (169133): Can't reserve pin GPIO_0[15] -- pin name is an illegal or unsupported format" So it's the standard setting, it might have an internal pullup enabled. Given the on off hobbyist experience, I don't know much about the board configuration, other than its a bidirectional ttl pin.

https://alteraforum.com/forum/attachment.php?attachmentid=15352&stc=1

I put all the lines to Z, it did show a decent square wave.

https://alteraforum.com/forum/attachment.php?attachmentid=15353&stc=1

When I run the previous arrangement it shows a good squarewave as well.

The problem arises when I connect extra lines to it. It instantly sags to a seemingly nominal level.