• 0

Rules of precedence for digital-out driving instruments?

Go to solution Solved by attila,




The Analog and Digital Discovery devices have multiple instruments that can drive the digital outputs:

  • DigitalIO
  • DigitalOut
  • UART, SPI, I2C, CAN protocols

What happens if multiple instruments are active simultaneously? Do some instruments have precedence over others?

Best, Sidney



Link to post
Share on other sites

3 answers to this question

Recommended Posts

  • 1

Hi @reddish

The digital IO signals are shared in the device between Digital-IO, Out and In functions. The Digital-IO has priority over Digital-Out. The Digital-Out is only applied for a signal when the Digital-IO Enable and Output are zero for the respective bit.

The protocols use the Digital-In/Out device resources to create various communication protocols. Only one of the protocols can be used at a time. The Digital-Out is used to generate the output signals and the Digital-In to capture the received data. Overriding a signal used by the protocol with Digital-IO may mess up the communication.
The I2C with clock stretching uses additional signals.
The DIO channe indexing for Digital Discovery starts from 0, 0 is DIO-24, 1 is DIO-25…

Link to post
Share on other sites
  • 0

Hi Atilla,

Thanks for the clarification.

Just to clear up one final thing about the relation between DigitalIO and DigitalOut device:

If the DigitaIO "OutputEnable" is 0,  and the DigitalIO "Output" is 1, what is then the state of the respective pin? Is it HighZ (irrespective of DigitalOut)?


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now