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C6713 pull up/down configuration for boot

Sean Bedford
Expert 1560 points

I think I may have found the problem.  I resorted to testing the output pins and GP13/HD13 is floating at about 1.5V.  My understanding is that this, along with other, pins are to do with the configuration process on reset and should be pulled up or down by an internal resistor.

So firstly could somebody please confirm that it should be pulled high or low?

As far as I can see, the data sheet doesn't actually tell you what the pin does that information would also be helpful in confirming that this is causing the problem.  Along with what state it should be in so I can try doing it externally in the hope that just the internal resistor is damaged.

As allways any help would be very much appreciated.

Sean

  • TI__Guru**** 171094 points

    Sean,

    I am glad that you are progressing; I will split this thread and put it in the C67x device forum so you can get more educated responses about the pull up/down pins and boot configuration. 

    Original thread:

    http://e2e.ti.com/support/development_tools/code_composer_studio/f/81/p/85287/299439.aspx

    Best regards,

    Rafael

     

  • TI__Expert 8785 points

    Based on Table 18 on page 33 of the datasheet, HD13 is not used to select the bootmode, only HD[4:3] are used.  HD12 and HD8 are used to configure your system.

    To determine which pins need an external resistor, please see the third footnote under the Terminal Functions table on page 50

    datasheet said:

    To ensure a proper logic level during reset when these pins are both routed out and 3-stated or not driven, it is recommended to include an external 10k pullup/pulldown resistor to sustain the IPU/IPD, respectively.

    So for pins that have the footnote symbol, you should add an external pullup/pulldown.

    Sean Bedford said:

    So firstly could somebody please confirm that it should be pulled high or low?

    It depends on the pin that needs the external pullup/pulldown.  Below is taken from the footnote under Table 18 of the datasheet.

    datasheet said:

    All other HD pins HD[13, 11:9, 7:5, 2:0] have pullups/pulldown (IPUs/IPDs).  For proper device operation, do not oppose the HD[13, 11:9, 7, 1, 0] pins with external pullups/pulldowns at reset; however, the HD[15, 6, 5, 2] pins can be opposed and driven at reset.

    --Christina

  • in reply to clam
    Expert 1560 points

    Hi Christina,

    Thank you for your reply.  I now HD13 isnt used to select the boot mode but if it can not be driven on reset is must have some affect on the reset process, do you know what this is?

    I am using the DSK so i assume what ever resistors are needed are there so the pin should high as it has an IPU but its at 1.5 V

    Sean

  • in reply to Sean Bedford
    TI__Expert 8785 points

    I spoke with the C6713 experts, and they confirmed that HD13 will need to be pulled high.  They said that there is some internal device configuration that is dependent on that pin.  Unfortunately, I do not know exactly which part of the device will get corrupted if it is not pulled high.

    Can you add the external pull up resistor to confirm if this will help with your boot issue?

    --Christina

  • in reply to clam
    Expert 1560 points

    Hi Christina,

    I added an external resistor but it didnt help.  I am also unable to drive HD13 as a GPIO pin so it seems there is internal damage to the DSP on this pin.

    Ideally I would just like it confirmed that this could be what is disruppting the boot process and not something else i am doing wrong.

    Sean

  • in reply to Sean Bedford
    TI__Expert 8785 points

    During boot, the bootrom will validate the HD13 signal.  If the HD13 signal is not pulled high, it will cause the bootrom to operate incorrectly, hence causing the device to not boot correctly.

    --Christina

  • in reply to clam
    Expert 1560 points

    Hey,

    Well I guess thats the answer to my question, although it cant really be solved it will give me more confidence in getting out in house board to boot correctly.

    Thanks you very much for your help Christina and Rafael, very much appreciated.

    Sean