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Instrument Control (GPIB, Serial, VISA, IVI)

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USB-8451 pull up resistor

Dear all,

 

I'm using the 8451 as i2c master, and for some reason (not important for this discussion) I need to use one of the 8451 pins as a 3.3V voltage source.I chose a DIO pin for the job and with Labview I managed to configure it properly to 3.3v with "push pull" driver type. My question is if there's an internal pull up resistors and if so, how could I configure it?

 

 

Thanks,

Or

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The USB-8451 does not have the built-in pull up resistor.  If you want to keep using the 8451, I would use the +5V output and then a 3.3V regulator to get your 3.3V.  You can then use 10k resistors for a pull ups.  Your other option is to just buy an USB-8452, which has the option to enable the I2C pull up resistors to 3.3V (or 1.2V, 1.5V, 1.8V, or 2.5V).


GCentral
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Thank you.

Are you familiar with a way to staticaly determine the sda or scl pins?

I would like to assign a logical '1' or '0' for a long period of time rather then just sending specific bytes with the labview's i2c writing example (which by the way,keep returning the msg I have attached)

 

Thanks again. 

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