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  • TI Thinks Resolved

TMS320C6652: TMS320C6652:Unused clocks/IOs

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Replies: 3

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Part Number: TMS320C6652

Hi,

In TMS320C6652CZHA6 I need clarifications on the below

1. MCIMCLKP / N

 I am not using MCIM in the design. These pins are mentioned are reserved in datasheet.Can these pins be left floating.

2.GPIO pins

Should we add pullup/pull down on GPIO input pins? I understand from datasheet GPIO outputs doesnot require pullup/down.

Also series termination to be used on GPIO outputs. Please confirm.

3. MDCLK

MDC is not used in the design. Can this pin be left floating?

Thanks,

Divy

  • Hi Divy

    I recommend referring to section 6.3.1 in datasheet for unused CLKN/P termination. 

    Additionally I recommend looking at the following schematic checklist 

    http://www.ti.com/lit/an/spracl9/spracl9.pdf

    Let me know if you have questions once you have reviewed these docs /sections for unused pin termination recommendations 

    Regards

    Mukul 

  • In reply to Mukul Bhatnagar:

    Hi Mukul,

    MCMCLKP/N are reserved for C6652 as per schematics.

    Should we add termination for reserved pin as well?

    Regards,

    Divya

  • In reply to Divy:

    Hi Divya

    Yes - this is somewhat covered in section 6.3.1 of the current datasheet.

    We are revising that datasheet to make it more clear (hopefully will release this updated datasheet by end of this month).

    Following will be the updated wording on section 6.3.1

    If a clock input is not used it must be held in a static state. To accomplish this the N leg should be pulled to ground through a 1 kΩ resistor. The P leg should be tied to CVDD to ensure it will not have any voltage present until CVDD is active. This includes the SGMIICLK and PCIECLK input pins that are reserved on the C6652 and MCMCLK which is reserved on both C6654 and C6652.

     

    Connections to the I/O cells powered by DVDD18 and DVDD15 are not failsafe and should not be driven high before these voltages are active. Driving these I/O cells high before DVDD18 or DVDD15 are valid could cause damage to the device.

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