3.4.8.2 MMC Interface
The AM64x processor provides two MMC interfaces. One MMC interface is connected to eMMC flash and the
other is used for the micro SD card interface.
3.4.8.2.1 Micro SD Interface
The processor board provides an uSD card interface connected to MMC1 port of AM64x SoC. The uSD
card interface supports UHS1 operation including operations at both 1.8V and 3.3V IO levels.. The AM64x
SoC includes a circuit to generate the uSD voltage based on IO level negotiation with the uSD card. For
high-speed cards, ROM code of the SoC attempts to find the fastest speed that the card and controller can
support and can have a transition to 1.8V. The internal SDIO LDO output from the SoC is provided on the
CAP_VDDSHV_SDLDO pin. CAP_VDDSHV_SDLDO is connected to both the IO voltage of SD signals and
VDDSHV_MMC1 power pins of the SoC.
Figure 3-15. Micro SD Interface
System Description
28
AM64x GP EVM User's Guide
SPRUIX0B – FEBRUARY 2021 – REVISED MARCH 2021
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