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I2C / TWI Master Mode Receive and Nak / Acknowledge

Question asked by AstroMedGlen on Apr 7, 2010
Latest reply on Jun 29, 2010 by AstroMedGlen



    I am having a problem with an I2C device and reading from it. I start a master mode receive conversation by sending the slave's address and the receive bit set high. The device should then respond by sending a stream of bytes back until I tell it to stop. I tell it to stop by using a high acknowledge. I can continuing reading by using a low acknowledge after each byte.

    My problem is that I can only receive one byte at a time because I always acknowledge high. Looking at the 21369 hardware reference manual, the acknowledge does not look programmable. At least not in master mode. I see that it might be in Slave mode.

    If my only solution was to operate in slave mode, how would that work? Could a send out the address byte in Master mode and quickly switch to slave receive before the device starts sending data back? I see this as the only solution and will probably start looking into it more after I finish this post.


   I attached a picture from the scope to help clarify the problem.


Thanks in advance,