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sensor interface - DM365 + OV

Ravikiran HV
Mastermind 8715 points

Hi all,

I am using a DM365 processor with minimal customization to it,. [so that we have our own board with DM365 as main processor.]

Now I am looking to interface a OmniVision sensor to it. This sensor is doesn't provide any clock facility. We need to provide a external clock to it.  Please find the schematic attached. This diagram explains the DM365  interfacing with sensor.

  1. By looking at the PinOuts, I assuem that, power up sequence is taken care by the circuit. I need not configure it from Software. 
  2. I did a Reset on SYS_RST (pin6).
  3. Now trying to configure VDOUT_CLK(pin 13).  By tracing this pin, it ended in VCLK/GIO79 of DM365. By loking at ARM Soc user guide of DM35, it is suggested to configure VCLK and PLL accrodingly. [Please find the image attached.]
    PLLC1 SYSCLK4  = 27MHZ
    PLLC2 SYSCLK5 = 27MHz
    PLLC1 SYSCLK6 = 27MHz

    Now   Configured the Pinmux such that it reads clock from PLL2 SySclock5[27MHz]

    But I am not able to communicate with my sensor  via I2C. So I feel I am missing something seriously.

    Appreciate any help on this.

  • 0
    TI__Expert 8780 points

    You need to check following 3 points:

    1. Reference clock is supplied to the sensor.

    2. Sensor is getting powered up appropriately.

    3. Reset pin is released for the sensor. Sometimes sensor boards expect a reset cycle which means that initially reset should be asserted and later deasserted. 

    Have you checked if above 3 are in order?

    Regards

    Rajat

  • 0 in reply to Rajat Sagar
    Mastermind 8715 points

    Hi Rajat,

    Thanks for the reply.

    I will cross check all the above mentioned points once again and update here.

    Before that I have 1 more query. Since My sensor is expecting the clock from DM365, Can I clock it from VPFE? If yes what is that pin we can use?

    I found GIO79/VCLK is actually input to the VENC module of VPBE.  If it is tru, then configuring VCLK alone with ABOVE 3 steps will be enough?

  • 0 in reply to Ravikiran HV
    TI__Expert 8780 points

    Ravikiranm

    VCLK is the pixel clock input to the SOC however what sensor board is expecting is the reference clock.

    You need to check what reference clock is expected by the sensor board.

    Regards

    Rajat

  • 0 in reply to Rajat Sagar
    Mastermind 8715 points

    Hi Rajat,

    If I see the schematic of sensor and DM365 interface, [schematic attached above], there is only one clock out line, i.e VDOUT_CLK whcih goes from DM365 Bord to sensor. So, this VDOUT_CLK is connected to VCLK/GPIO79 pin. When you mentioned reference clock for sensor, is it some thing different from this? This VDOUT_CLK can't cat as reference clock for sensor ?

    Other clock line which I found on schematic is PCLK, but I assume this PCLK should be the input for DM365. ie.e PCLK need be supplied by sensor to drive pixels to DM365.