Altera cyclone V Technical Reference page 1024

14-78
Boot Operation for Removable MMC4.3, MMC4.4 and MMC4.41 Cards
can then initiate a data read from the controller based on the
register.
In internal DMA controller mode, the DMA engine starts transferring the data from the FIFO
buffer to the system memory as soon as the level specified in the
register is reached.
At the end of a successful boot data transfer from the card, the following interrupts are generated:
• The
• The
c. In internal DMA controller mode:
• If the software driver creates more descriptors than required by the received boot data, the extra
descriptors are not closed by the controller.
• If the software driver creates fewer descriptors than required by the received boot data, the
controller generates a Descriptor Unavailable interrupt and does not transfer any further data to
system memory.
The boot operation for eMMC card devices is complete.
Related Information
Clock Setup
•
Refer to this section for information on how to set the card device frequency.
Internal DMA Controller Transmission Sequences
•
Refer to this section for information about the Internal DMA Controller Transmission Sequences.
Internal DMA Controller Reception Sequences
•
Refer to this section for information about the Internal DMA Controller Reception Sequences.
Boot Operation for Removable MMC4.3, MMC4.4 and MMC4.41 Cards
Removable MMC4.3, MMC4.4, and MMC4.41 Differences
Removable MMC4.3, MMC4.4, and MMC4.41 cards differ with respect to eMMC in that the controller is
not aware whether these cards support the boot mode of operation when plugged in. Thus, the controller
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must:
1. Discover these cards as it would discover MMC4.0/4.1/4.2 cards for the first time
2. Know the card characteristics
3. Decide whether to perform a boot operation or not
Booting Removable MMC4.3, MMC4.4 and MMC4.41 Cards
For removable MMC4.3, MMC4.4 and MMC4.41 cards, the software driver must perform the following
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steps:
1. Discover the card as described in Enumerated Card Stack.
2. Read the EXT_CSD register of the card and examine the following fields:
• BOOT_PARTITION_ENABLE
• BOOT_SIZE_MULT
• BOOT_INFO
3. If necessary, the software can manipulate the boot information in the card.
Note: For more information, refer to "Access to Boot Partition" in the following specifications available
on the JEDEC website:
Altera Corporation
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bit and bit in the
cmd dto
bit in the register, in internal DMA controller mode only
ri idsts
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on page 14-46
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register
rintsts
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on page 14-59
on page 14-59
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interrupt bit in the
rxdr
field of the
rx_wmark
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SD/MMC Controller
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cv_5v4
2016.10.28
rintsts
fifoth
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