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What does the MIO pullup option in Vivado PS configuration wizard IO window do?

Adventurer
Posts: 95
Registered: ‎08-05-2012

What does the MIO pullup option in Vivado PS configuration wizard IO window do?

Hello, I am trying to communicate with an I2C slave that requires 1.5 kOhm pullup resistors on SCL/SDA.  I was going to solder in physical resistors myself, but then remembered the pullup column in the Vivado configurator (attached).

I can change the "disabled" to enabled easily enough, but I cannot find any documentation on what pullup resistor values is used in Zynq.  On the MIO pins, the pullup can be en/disabled through MIO register, so I wondered what this pullup option does exactly.  Can you please refer me to a documentation that lists the pullup resistor values used inside the Zynq chip?

Scholar
Posts: 1,180
Registered: ‎11-09-2013

Re: What does the MIO pullup option in Vivado PS configuration wizard IO window do?

WEAK, need add extra R pullup or then use 10khz clock when only internal pullup is available

Adventurer
Posts: 95
Registered: ‎08-05-2012

Re: What does the MIO pullup option in Vivado PS configuration wizard IO window do?

Thank you!
So internal pullup can only be used if fSCL < 10 kHz? Where can I find that documentation please?
Scholar
Posts: 1,180
Registered: ‎11-09-2013

Re: What does the MIO pullup option in Vivado PS configuration wizard IO window do?

nowhere.

 

it is so, when I say so.

 

36 years of experience, it is heavy but I carry on

 

:)

 

it probably works bit above 10K also, but 10K is safe bet.