The TI E2E™ design support forums will undergo maintenance from Sept. 28 to Oct. 2. If you need design support during this time, contact your TI representative or open a new support request with our customer support center.

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DLPDLCR4710EVM-G2: DLPDLCR4710EVM-G2: I2C Communications Issues, I2C bus bussy.

Part Number: DLPDLCR4710EVM-G2
Other Parts Discussed in Thread: DLPC3439,


In our DLPDLCR4710EVM-G2 module we are able to talk (via I2C) with the DLPC3439 chip and read/write parameters, the problem is that the communication bus seems very busy (it looks like something is talking with the IT6801 device) this makes communication unreliable.
Now, using the Windows DLP Advance GUI and running a batch file it seems the "background communication" (to address 0x90) stops! this leaves the bus free and the commands running trough the it never find it busy.

Is there a way to completely free the i2c bus preventing communication issues?

  • Hello User,

    What you are asking for is possible. In particular, please see the schematic for this EVM:

    What you should be focusing on is GPIO5 and GPIO9 of the Cypress USB chip (U48) in the schematic. Their functions are as follows:

    GPIO5 - MSP430_REQ - ON when Cypress CY3420 requests the MSP430 to give Cypress master control of the I 2C bus

    GPIO9 - Blinking when PC is communicating to flash over SPI

    If you write to the Cypress USB device and tell it to drive GPIO 5 high, and then drive GPIO9 high, you should be able to tell the MSP430 on the board to yield control of the I2C bus to the Cypress. Once you have done these things, you will be able to send uninterrupted I2C commands to the DLPC3439.

    I hope this helps.


    Philippe Dollo