Hello,
Basically there are no differences in uSDHC ports of i.MX6SX.
From Table 2 (i.MX 6SoloX Modules List) of i.MX6SXDataSheet(s).
All four MMC/SD/SDIO controller IPs are identical and are based on the uSDHC IP.
They are:
Fully compliant with MMC command/response sets and Physical Layer as defined
in the Multimedia Card System Specification, v4.5/4.2/4.3/4.4/4.41/ including
high-capacity (size > 2 GB) cards HC MMC.
Fully compliant with SD command/response sets and Physical Layer as defined in the
SD Memory Card Specifications, v3.0 including high-capacity SDHC cards up to 32 GB.
Fully compliant with SDIO command/response sets and interrupt/read-wait mode as
defined in the SDIO Card Specification, Part E1, v3.0.
Conforms to the SD Host Controller StandardSpecification version 3.0.
All four ports support:
1-bit or 4-bit transfer mode specifications for SD and SDIO cards up to UHS-I SDR104 mode (104 MB/s max)
1-bit, 4-bit, or 8-bit transfer mode specifications for MMC cards up to 52 MHz in both
SDR and DDR modes (104 MB/s max)
All ports can work with 1.8 V and 3.3 V cards. Each port is placed on a separate power domain.
It makes sense to follow NXP referenece design(s) if software compatibility with NXP BSPs is needed.
Have a great day,
Yuri
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