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DS90UB914&DS90UB913

Qin Shan
Prodigy 20 points
Other Parts Discussed in Thread: DS90UB914Q-Q1
I have some questions about DS90UB914.
 
My system include sensor MT9M034 and DS90UB913 and DS90UB914.I use external oscillator mode in MT9M034 and DS90UB913.GPO3  pin on the DS90UB913 inoputs 50M external oscillator,GPO2 outputs 25M.I connect the 25M to MT9M034 as reference clock. But MT9M034 won't output pixclk unless 914 completes I2C configuration about  MT9M034.
 
Now the ID of  914,913,MT9M034 and the Alias of 914,913,MT9M034 are correct.The pin LOCK is hign.,but serial link has not signal.why?
 
If 914 need reference clock when it translate signal to serial link?Now 914 has no reference clock.
 
 
 
 
 
 
 
 
Thank you for your support in advance.
Regards,
QIN SHAN
  • 0
    TI__Genius 13475 points

    The 914 should not require a reference clock for the backchannel to operate properly.   Are you able to determine if the backchannel is operating by reading and writing registers in the DS90UB913 via the DS90UB914?

  • 0 in reply to Mark Sauerwald88474
    Prodigy 20 points

    Mark Sauerwald

    My operation is as follows:

     Register list of 914: 0318,06B0(SER ID,0X58<<1),07B2(SER Alias,0x59<<1) ,0840 ,1040 ,1F02 ,1F92 ,3F00

    Operation writing to 914:0x60 + Register Address + parameters.

    Operation writing to 913:0x59 + Register Address + parameters.

    My questions is as follows:

    (1) Now 914 has ACK when I configure 914's registers .But 913 has not  ACK when I configure 913's   registers.913's power state is normal,914's LOCK is high.I don't know why 913 has not ACK signal?

    (2)MY system is as follow:Camera sensor MT9M034 and DS90UB913 and DS90UB914 and FPGA.I use external oscillator mode.Crystal oscillator 50M is connected to GPO3 of 913,  GPO2 of 913 has 25M output.I use this  25M as MT9M034's refenence clock.Simultaneously 914's pin_8 namely pclk has 75M output(12 bits high frequency mode). But at this time MT9M034's has not pclk output because it needs register configurations by I2C from 914 and 913.I don't know if 913 can output ACK signal when FPGA communicates with 913 under the contion MT9M034 has no pclk output to 913?

    (3)I don't understand the Powerdown of page 49 in ds90ub914q-q1.pdf. If MT9M034 has no pclk outoput to 913,can 913 and MT9M034's registers  be configurated?If not,how can I configure the MT9M034 bccause it won't has pclk output until its registers about pclk are  configurated by I2C.

  • 0 in reply to Qin Shan
    TI__Genius 13475 points

    (1)  When you are writing to the 913, are you writing directly through the I2C port on the '913, or are you attempting to write via the backchannel?

    (2)  I am not very familiar with the MT9M034 sensor - if you are using external oscillator mode, the device expects a specific relationship between the pixel clock frequency and the external oscillator frequency.   For the 12 bit high frequency mode the Pixel clock frequency divided by the external clock frequency must be 1.5 - therefore if you have a 75MHz pixel clock, you would be using a 50MHz external oscillator.

    (3) you can enter a low power mode with the PDB pin.   During debug of the I2C, I would recommend holding PDB high.  Usually PDB has a resistor to Vdd and a capacitor connected to GND, and is set such that PDB is low when first powered up, and the time constant of the RC is long enough to allow the power supplies to stabilize prior to enabling the device.