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Original question:

DLPDLCR4710EVM-G2: Technical details and usage of trigger input & output pins on DLP LightCrafter Display 4710 EVM-G2

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

user4081360
Prodigy 30 points
Part Number: DLPDLCR4710EVM-G2
Other Parts Discussed in Thread: DLPC3439,

Hi,

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?

  • +1
    TI__Mastermind 28005 points

    Hello User,

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

    https://www.ti.com/lit/df/tidrnb9/tidrnb9.pdf

    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.

    Regards,

    Philippe Dollo