From: Dave H. <dhy...@gm...> - 2010-06-24 23:48:31
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Hi Matt, On Thu, Jun 24, 2010 at 11:14 AM, Matt Singer <ms...@ea...> wrote: > Dave, > > How are using that SparkFun board for the SDA line? SCL is obviously a a > transmit, but SDA is bi-directional. Nope both lines are bi-directional. The slave device is allowed to stretch the SCL clock by driving it low. The master releases SCL, and then has to monitor and wait ti detect that its gone high before it can continue with the next bit. The way that the MOSFET is used allows for bi-directional voltage conversion. See this document for background on how it works: <http://www.nxp.com/documents/application_note/AN10441.pdf> -- Dave Hylands Shuswap, BC, Canada http://www.DaveHylands.com/ |