Good day

I would like to read the analog output value of one microcontroller with another microcontroller. Is it safe to connect the dac pin of the one microcontroller directly to the adc pin of the other microcontroller or do I need to add a resistor in between to limit the current draw from the microcontroller that is generating the analog signal

 

Hey Edmar. Welcome to the forums.

Your scheme is fine. Analog inputs are high impedance meaning they draw little to no current.

Hint: why use two microcontrollers when one micro can read it's own output?

 

Hey Edmar. Welcome to the forums.

Your scheme is fine. Analog inputs are high impedance meaning they draw little to no current.

Hint: why use two microcontrollers when one micro can read it's own output?

Hi, thank you for the reply. The reason for this is that I have one microcontroller that is controlling an ac heating element therefore it is handling the zero crossing detection interrupts. The main microcontroller is handling all of the other tasks of the system. I found that when I had the heating element control on the same microcontroller that is controlling the process, handling bt communications, computing fuzzy logic inputs etc., the controller is not able to execute all of the instructions without being interrupted. This causes parts of code simply not executing. Therefore my solution to this was to give the heater control micro an analog voltage that gives the heating output. I had to do this probably due to my inexperience in handling multiple large tasks.

 

Maybe this is too obvious to mention, but just to make sure it is covered, make sure the output of the DAC does not exceed the input range of the A-to-D. For example a DAC with a 0 to 5V output would not work well driving an A-to-D converter with an input range of 0 to 3.3 volts.