Functional Description
Table 26-19. Pins Used for NAND Boot (continued)
Signal name
Pin Used in Device
OEN_REN
GPMC_OEN_REN
BE0N_CLE
GPMC_BEN0_CLE
WEN
GPMC_WEN
WAIT
GPMC_WAIT0
CLK
GPMC_CLK
AD0 - AD15
GPMC_AD0 - GPMC_AD15
26.1.7.4.2.3 SYSBOOT Pins
SYSBOOT[11:10] has a special meaning when NAND boot is selected. SYSBOOT[11:10] must be 0.
26.1.7.5 MMC / SD Cards
26.1.7.5.1 Overview
The ROM Code supports booting from MMC / SD cards in the following conditions:
•
MMC/SD Cards compliant to the Multimedia Card System Specification and Secure Digital I/O Card
Specification of low and high capacities.
•
MMC/SD cards connected to MMC0 or MMC1.
•
Support for 3.3/1.8 V on MMC0 and MMC1.
•
Initial 1-bit MMC Mode, optional 4-bit mode, if device supports it.
•
Clock Frequency: identification mode: 400 KHz; data transfer mode up to 10 MHz.
•
Only one card connected to the bus.
•
Raw mode, image data read directly from sectors in the user area.
•
File system mode (FAT12/16/32 supported with or without Master Boot Record), image data is read
from a booting file.
26.1.7.5.2 System Interconnection
Each interface has booting restrictions on which type of memory it supports: -
•
MMC0 supports booting from the MMC/SD card cage and also supports booting from
eMMC/eSD/managed NAND memory devices with less than 4GB capacity.
•
MMC1 supports booting from eMMC/eSD/managed NAND memory device with 4GB capacity or
greater.
The restriction is a result of many eMMC devices not being compliant with the eMMC v4.41 specification.
If you have the need to boot from two different card cages, many MMC/SD cards will boot from MMC1, but
for maximum compatibility only MMC0 should be used to boot from the card cage. Similarly for maximum
compatibility, booting from eMMC/eSD/managed NAND should only be performed on MMC1.
Note that the above restrictions only apply to booting from each port. Drivers can be written for either port
to support any desired interface.
Note:
•
The ROM Code does not handle the card detection feature on card cage.
•
If MMC1 is used the GPMC interface is not usable, due to pin muxing options.
•
MMC1 supports sector mode without querying the card.
4129
SPRUH73H – October 2011 – Revised April 2013
Initialization
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