Changes between Version 22 and Version 23 of MMC


Ignore:
Timestamp:
04/07/2022 08:25:56 PM (8 months ago)
Author:
Tim Harvey
Comment:

added note about eMMC hardware partitioning limitations

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  • MMC

    v22 v23  
    113113Because eMMC provides multiple hardware partitions but only one can be selected at a time. A non-volatile register in the eMMC device provides a PARTITION_CONFIG that is used to determine what partition is selected at power-up for boot devices. To access this data you need to read/write a 'Card Specific Data' or CSD register (EXT_CSD[179] - EXT_CSC_PART_CONFIG). This can be done both in Linux (see [#emmc-linux below]) or U-Boot (see [#emmc-uboot below]).
    114114
     115Note that changing your eMMC partitioning differs a bit for each eMMC part (Manufacturer make and model) and needs to be done very early on as it can't succeed after a certain number of writes have occurred. If you need a specific partition configuration for a high volume product contact sales@gateworks.com for more info.
    115116
    116117[=#emmc-enhanced-user-area]