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AM5716: CSS bit in MMCHS_PSTATE register

Part Number: AM5716

Hi,

I have a question about CSS bit (and CINS bit) in MMCHS_PSTATE register. Although this bit is described as a test bit, will it actually change when an SD card is inserted or removed? Or does it change only when  CDSS  bit  = 1 and CDTL bit in MMCHS_HCSTL register are changed?

Best Regards,

M.Ohhashi

  • Hi Masashi,

    Refer to Table 25-21. eMMC/SD/SDIO Hardware Status Features

    It explains that MMCHS_PSTATE[17] CSS status bit indicates whether mmci_sdcd card detect pin level is stable (0V/1.8V/3.3V)  or not (debouncing).

    Regards,
    Pavel

  • Hi Pavel-san,

    Thank you for your reply.

    CSS bit of MMCHS_PSTATE[17] in Table 25-21 and 25-98 described "Used for testing". Does this bit (CSS) indicate the current status (stable or not) when both CDSS in MMCHS_HCTL is 0(for normal use) and 1(for test purpose)?

    Best Regards,

    M.Ohhashi

  • M.Ohhashi,

    Masashi Ohhashi said:
    Does this bit (CSS) indicate the current status (stable or not) when both CDSS in MMCHS_HCTL is 0(for normal use) and 1(for test purpose)?

    No. Per mine understanding, CSS bit is valid (indicate the current status, stable or not) ONLY when MMCHS_HCTL[7] CDSS = 0x0 (mmci_sdcd selected).

    MMCHS_HCTL[7] CDSS = 0x1 is ONLY used for manual control of MMCHS_PSTATE[16] CINS. Please refer to below AM571x TRM section:

    25.4.16 Test Registers

    But please note that I have not verified this on AM57x board.

    Regards,
    Pavel