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Schematic Review ADV7282M

I wanted to make PAL camera board based on adv7282m below is my schematic , requesting for kind review and comments, i wish to interface this board to raspberry pi CSI CAM connector

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[edited by: shyam.sunder91 at 10:10 AM (GMT -5) on 2 Dec 2021]
  • 1) MCLK is a source and should be connected to XTALP.  XTALP is the input and XTALN is an output.  

    2) Why the 560 Ohm resistor in the crystal circuit.  Doesn't hurt. Might have to tweak crystal load caps depending on crystal.

    3) Use solid ground plane.  EPAD is connected to ground, (you don't know how often this is missed)

    Looks good

  • Kindly answer point wise.

    1. My current issue is i am not able to get any I2c response from my daughter board if the address is x43, i am getting some response from 0x44 which is confusing

    i2cget -y 2 0x44 0x00 returns me 0x80 from my xavier nx board connected over CAM0

    went forward and tried to read 0x11 which should return me chip id as 0x43

    but the result is 0x12

    2.The PWDN pin was earlier low due to my carrier board so i have removed that connection still there is no response from I2C

    the pwdn pin is reading now 3.17v hope this is with in limits, please confirm

    3.3.3V is read at reset pin, i have remove the reset circuitry and pulled it up through 4.7k

    4. This is a extract from datasheet, please confirm above contradiction

    anyway I am currently using crystal input, MCLK is not shorted.

    5. 560 Ohm usage is extracted from the reference schematic

    6. Layout is taken care, you may throw some comments on it to .

    Thanks

  • 1) The device should only respond to 0x40,41,42,43 depending on how ALSB is pulled.  With a scope, see if the device is really returning the ACK bit.  Also keep in mind that this is an 8-bit address while many drivers work with 7-bit addressing.  You'd need to right shift our address by one to get the 7-bit address.  Even addresses are write addresses while odd addresses are reads

    2) PWRDWN should have a weak pull up.  It may float to 3V or so.  

    3) A weak pull up on RESET is good

    4) Yes, your are right, XTALN is the input.  Other chips have XTALP as the input.  Sorry

    5) 560 is not a problem

    6) Layout, I'm assuming there is a solid ground plane not shown.  Traces are 50 Ohms.  Curved analog inputs are nice but not needed. OK to leave.

  • i2cget -y 2 0x21 0x11 returns me 0x34 over CAM0 as per expectation

    so i assume there is not problem with i2c communciation, i assume as of now no problem with data interface also would come back if any key issues are identified

    can you let me know the default settings of the chip, what will be output format and what will be the output frame rate and format, it would be great if a default register map is available for the device.

  • Glad to hear I2C is working correctly.  The 7/8 bit addressing always comes up.

    The ADV728x Hardware Manual has the default reset settings

    More information on the part can be found here.

  • I am stuck in one more issue, i am not seeing the CSI_CLK_P and CSI_CLK_N , what could be the problem ? but the MIPI data is available. 

    the crystal output is also proper

    is anything configured wrong on above schematic ?

    i am using the same driver provided by analog