using multiple pins of ni 6501 to implement i2c

[ravi_mehta]

NI USB 6501 supports open drain outputs. But, I2C is tough to implement (according to multiple users on this forum) because direction change and tristating are not supported per cycle. Can the following method be used to make it work?

Configure one IO for SCL (P0.0), one IO for SDA output (P0.1) and one IO for SDA input (P0.2). Now, short P0.1 and P0.2 externally. In this way, it should be possible to do I2C in spite of the fact the per cycle direction change is not allowed.

Comments?

-Ravi

[SnowMule]

NI makes a USB-I2C adapt-o-matic... probably worth the money to get the hardware done and have all the VI's necessary to control it rather than reinvent the wheel yourself.

http://sine.ni.com/nips/cds/view/p/lang/en/nid/202368

[ravi_mehta]

Thanks for your reply. I am aware of USB 8451. However, for various reasons, I would like to stick to USB 6501. Can you please share your opinion on how feasible the 'reinventing-the-wheel' scheme sounds?

Regards,

Ravi

[SnowMule]

The 6501 is software-timed, so you're going to have a lot of variation because of the USB and PC.

Plus you'd have to write all the VI's to do the I2C-Digital conversion.

The 6501 isn't a bad board, but it sounds like the wrong board for your application. The 8451 has a handful of DIO's you can use in addition to I2C.

[lin123]

Hi Ravi,

I am trying to use NI 6501 to implement i2c communication recently. Did you successfully perform the communication with 6501?

Lily