i2c interface question

Discussion in 'Programmer's Corner' started by martin_k, Sep 12, 2005.

  1. martin_k

    Thread Starter New Member

    Sep 12, 2005
    Has anybody tried to use i2c interface adapter from Dimax? I have bought one at: usb-i2c adapter.
    I2c interface adapter was supplied with ControlPanel application.
    This i2c interface control panel has a lot of buttons. Most of them are well understood, like I2cRead, I2cWrite, Start, Stop...
    But there are also several buttons: ReleaseSCL, DropSCL, ReadSCL. Same buttons are with SDA at the end. All of them are grouped at “i2c interface wire level commands bar”.
    When I press on the Release and Drop buttons, only the messages “i2c interface command succeeded” appear.
    May be somebody knows what do this buttons do?
  2. anders

    New Member

    Sep 12, 2005
    I have used this i2c interface adapter over a long period. It has three levels of i2c bus interface as you can see in its documentation.
    1. I2c interface high level routines: I2cRead and I2cWrite functions (you mentioned that already understand their meaning).
    2. I2c interface low level routines: Start, stop, read/write byte etc.
    3. I2c interface wire level routines (you are asking about). I2C bus is 2-wire serial interface. These wires (i2c bus specification calls them lines) are: serial data line (SDA) and serial clock line (SCL). Both of lines have pull-up resistors to VDD. So, when they are “released”, i2c interface has logical “1” on these lines. When they are “dropped”, i2c interface adapter outputs logical “0”. It’s correct that you receive “i2c interface command succeeded” message. You can measure voltage level at i2c bus lines and find it changed.
    Take a look at Philips i2c bus specification for complete description of i2c bus lines.
  3. znatok

    New Member

    Jul 1, 2009
    Mentioned product is obsolete and replaced with SUB-20 (snip).
    Any references? I need it to test my I2C master.
    Last edited by a moderator: Jul 28, 2009