Altera cyclone V Technical Reference page 1029

cv_5v4
2016.10.28
• The
• The
e. 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 alternative 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.
Alternative Boot Operation for MMC4.3 Cards
Removable MMC4.3 Boot Mode Support
Removable MMC4.3 cards differ with respect to eMMC in that the controller is not aware whether these
cards support the boot mode of operation. Thus, the controller 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
Discovering Removable MMC4.3 Boot Mode Support
For removable MMC4.3 cards, the software driver must perform the following steps:
1. Discover the card as described in Enumerated Card Stack.
2. Read the MMC card device's EXT_CSD registers and examine the following fields:
• BOOT_PARTITION_ENABLE
• BOOT_SIZE_MULT
• BOOT_INFO
Note: For more information, refer to "Access to Boot Partition" in JEDEC Standard No. JESD84-A43,
available on the JEDEC website.
3. If the host processor needs to perform a boot operation at the next power-up cycle, it can manipulate
the contents of the EXT_CSD registers in the MMC card device, by using a SWITCH_FUNC
command.
4. After this step, the software driver must power down the card by writing to the
5. From here on, use the same steps as in Alternative Boot Operation for eMMC Card Devices.
Note: Ignore the EBE if it is generated during an abort scenario.
If a boot acknowledge error occurs, the boot acknowledge received interrupt times out.
SD/MMC Controller
Send Feedback
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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Alternative Boot Operation for MMC4.3 Cards
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register
rintsts
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on page 14-59
on page 14-59
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register.
pwren
Altera Corporation
14-83
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