I2C two master on one I2C display


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  1. #1
    Join Date
    May 2004
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    Default I2C two master on one I2C display

    Is it possible to have 2 master I2C on one I2c display?

    Like this Master1 Line 1 on the display
    Master2 Line 2.

    I found this on the net

    Arbitration
    As the I2C bus is a multi-master bus it is possible that two devices initiate a transfer at the exact same
    time (e.g. RTC tick). When this happens the first device attempting to transmit a logical 1 while another
    device transmits a logical 0 will lose arbitration. The device attempting to transmit 1 will detect that the
    line is low when it should actually be high so assumes that another master is active and immediately
    stops its transfer. This device will then wait until the next STOP condition before trying to transmit again.

    Or do I have to use a 2 to 1 master selector like PCA9541.

    Kent

  2. #2

    Default Re: I2C two master on one I2C display

    I have used two pics to access DS1307 some years ago, I put 470ohm resistors in line on each of the pics and used a similar connection between the 2 pics as a busy line. ( probably not the correct way - but it worked fine)

    Then some simple programming of setting and reading the busy line, always making sure that when not busy, the line on each is set to an input.

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