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TMS320C6745: SD card

Yasushi Fujiwara
Genius 12725 points

Part Number: TMS320C6745
Other Parts Discussed in Thread: TMS320C6748

Hello Experts,

My customer is adopting C6748 for many products. Customer is using SD card with C6748. Customer is now looking at C6745 and customer would like to know whether C6745 can connect to SD card. If yes, is there any differences between C6745 and C6748, SD card connection point of view?

Best Regards,
Fujiwara

  • 0
    TI__Guru 64655 points

    I spotted two differences that need to be considered.

    The C6748 defines different timing parameter limits associated with the MMCSD ports based on its core operating voltage. That is not the case for C6745. The C6745 only defines a single set of timing parameter limits for the MMCSD port. Therefore, you should compare how the timing parameters differ between the two devices at the respective operating points to ensure you will get the same results with your SD Card.

    The other difference is the C6748 device supports dual voltage IOs, where the C6745 device only supports 3.3V IOs. You will need to operate the IOs connected to the SD Card at 3.3V, which means you will also need to operate all devices connected to IOs within the same power group at 3.3V.

    Regards,
    Paul

  • 0 in reply to peaves
    TI__Genius 12725 points

    Hello Paul,

    The MMSD of TMS320C6745/TMS320C6748 can be connected eMMC, right?

    Best Regards,
    Fujiwara

  • 0 in reply to Yasushi Fujiwara
    TI__Guru 64655 points

    Your customer will need to perform a timing analysis of the eMMC device and the TMS320C6745/TMS320C6748 devices to understand how much time is allowed for PCB delays. The eMMC device may need to be placed close to the TMS320C6745/TMS320C6748 device to make sure the combined PCB delay of the clock going to the eMMC device and the data returning to the TMS320C6745/TMS320C6748 device doesn't cause a setup time violation for the TMS320C6745/TMS320C6748 device.  I mention this because some eMMC devices may not provide more than 5ns of setup and you must subtract the PCB delays from that and still provide some margin for the TMS320C6745/TMS320C6748 device. The TMS320C6748 device will be the most difficult because it requires 4.5ns of the 5ns for CMD setup.

    Regards,
    Paul