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PSoC 4 MCU

Anonymous
Not applicable

  When I use I2C master module, I use I2C_start() function, then use I2C write function. But I can't see any signal by logistic analysis.

   

But I2C_writebuffer function can work well. What's the reason? Do I miss to call some function?

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Esteemed Contributor II

Welcome in the forum!

   

You need to call at first I2C_SendStart() API.

   

Byte I2C interface is quite simple: After setting up the component and starting it you use

   

    I2C_MasterSendStart(DeviceAddress,I2C_WRITE_XFER_MODE);    // Initialize a transaction for writing
    I2C_MasterWrite(Register);                // Indicate which register you want to write to
    I2C_MasterWriteByte(Value);                // Write to register
    I2C_MasterSendStop();                    // End of transaction

   

When you want to read from a device you use (example for reading two bytes

   

    I2C_MasterSendStart(DeviceAddress,I2C_WRITE_XFER_MODE);    // Initialize a transaction for writing
    I2C_MasterWrite(Register);                // Indicate which register you want to write to
    I2C_MasterSendRestart(DeviceAddress,I2C_READ_XFER_MODE);
    I2C_MasterReadByte(I2C_ACK_DATA);            // Read from register
    I2C_MasterReadByte(I2C_NAK_DATA);            // Read from register, last byte is NAKed
    I2C_MasterSendStop();                    // End of transaction

   

Not too difficult. Keep in mind that most of the APIs (except those for reading a byte) return a status byte which, when non-zero indicate an error condition.

   

Bob

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Anonymous
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Thanks for your great support! Bob, now the module works well.

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Esteemed Contributor II

You are always welcome!

   

 

   

Bob

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