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mike239955_stm1_stmicro
mike239955_stm1_stmicro
Associate
September 23, 2015
Question

I2C and Omnivision SCCB and ACK

  • September 23, 2015
  • 1 reply
  • 1100 views
Posted on September 23, 2015 at 04:00

I'm trying to interface with an OV7725 image sensor. Omnivision has their SCCB which is very similar to I2C but does not generate an ACK bit. It seems like the STM32F407 (and maybe others in the product line, but that's what I have right now) gets into a state where it does not want to send any more data once it does not get the ACK it wants after the address is sent. So what's happening is when I send the address and don't get an ACK, I can't send any more data, even if I clear the AF bit and keep writing things to the DR register. Is there some way to make it ignore the no-ACK? Or am I doing something wrong?

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    1 reply

    Amel NASRI
    Amel NASRI
    ST Technical Moderator
    October 1, 2015
    Posted on October 01, 2015 at 14:58

    Hi Mike,

    This is the I2C protocol: for all STM32 products, the master waits for Slave ACK after the Slave address.

    -Mayla-

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