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TMS320C5517: UHPI of C5517

Masashi Ohhashi
Expert 4805 points
Part Number: TMS320C5517

Hi,

my customer will use UHPI of C5517. They would like to confirm the behavior of the pins after reset release.  The chip select signal (EM_SDCAS / UHPI_HCS) in UHPI belongs to Z, High Group immediately after reset release, so they think that High is output from the terminal. Normally, UHPI_HCS is used by connecting it to the CS signal of the host CPU. However, since the CS signal of the HOST CPU is naturally output, signal collision is considered to occur. There are several such signals, but is it necessary to provide an external circuit configuration that does not cause collision by gate control?

If necessary, please tell us which signal should be used to check the gate switching timing. They believe that two gates are required when switching DSPs.

(1) At the transition from reset release to UHPI Boot Mode -> At what timing after Reset release does the UHPI pin setting complete?

(2) When processing is passed from Boot Loader to Main Program -> The timing when the Boot Loader invalidates UHPI (is the terminal state the same as in (1) at this time?) And passes the processing to the main program

Best Regards,

M.Ohhashi

  • 0
    TI__Guru 50170 points

    Hi,Masashi,

    I have looped in hardware expert to see if he can answer your questions.

    Rex

  • 0
    TI__Guru* 83975 points

    Hi Ohhashi-san

    Sorry for the  extreme delay in getting back to you on this thread.
    After some additional internal discussion with Mark, here is our response

    These HPI signals in the “Z, High Group” default to pinmux PPMODE 1 (EMIF), so they are outputs meant for an SDRAM or Flash.
    HPI pins in Z, High Group: EM_DQM0/UHPI_HBE0, EM_DQM1/UHPI_HBE1, EM_SDCAS/UHPI_HCS, EM_SDRAS/UHPI_HAS
    As per the documentation, it the weak internal pull downs are enabled at reset for these pins – any output driven high will override these pulls and can be checked with the EVM.

    Customer need gates or tailored host software to prevent external contention during the time from reset to bootloader running and the time from the bootloader start to HPI copy time.

    The UHPI boot can be evaluated on C5517 EVM using the on board MSP430 as the external Host. The www.ti.com/.../sprabp1a.pdf 2.2.8 has the detailed steps. The www.ti.com/.../spruhw2.pdf has the boot mode settings (table 3) and the UHPI example

    If needed we may also be able to provide the relevant c5517 boot loader key source code (as is) , if that helps to look at relevant signals and timing.

    Does your customer has the EVM where they can do this analysis with C5517 EVM with MSP430 HPI boot?

    Hope this helps.

    Regards

    Mukul