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What about Analog Outputs?

billabott

It is easily understood that the Arduino family of microcontrollers are able to do digital input and digital output with  digitalRead() and digitalWrite().  And because of the onboard ADC the UNO and others can do analog input using analogRead(). 

 

But, what about the need for analog output?  Like when the LED really needs to gently brighten and dim slowly rather that the harshness of instant full on and instant off.  Atmel certainly could have added a few hundred more transistors to the silicon die and included an onboard DAC.  They did not.

 

Would the UNO be better if they had included the DAC?

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    I could see a few different reasons they didn't want to include it. 

     

    First would be cost.  Always better to keep cost down.

     

    Second would be that different DACs are used for different things.  An audio DAC is much different from one that is used to drive a motor or dim a light.

     

    Third would be power.  Most devices that you want to drive with a dac use a fair amount of power.  The output from the processor's DAC would be basically limited to an LED or two and that's it. 

     

    Fourth would be robustness.  Motor drivers, fets, and pretty much and switching device are prone to burning up if put in the wrong conditions.  If you burnt a motor driver DAC up would you rather buy a whole new AVR or just pop the motor driver out of it's socket and replace just it?

     

     

     

    The only thing I would use a built in DAC for would be for a code adjustable VREF.  Would be nice that if you knew a sensor would never go above 2.2 volts to cap the VREF at that.

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  • 0

    I could see a few different reasons they didn't want to include it. 

     

    First would be cost.  Always better to keep cost down.

     

    Second would be that different DACs are used for different things.  An audio DAC is much different from one that is used to drive a motor or dim a light.

     

    Third would be power.  Most devices that you want to drive with a dac use a fair amount of power.  The output from the processor's DAC would be basically limited to an LED or two and that's it. 

     

    Fourth would be robustness.  Motor drivers, fets, and pretty much and switching device are prone to burning up if put in the wrong conditions.  If you burnt a motor driver DAC up would you rather buy a whole new AVR or just pop the motor driver out of it's socket and replace just it?

     

     

     

    The only thing I would use a built in DAC for would be for a code adjustable VREF.  Would be nice that if you knew a sensor would never go above 2.2 volts to cap the VREF at that.

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