Altera cyclone V Technical Reference page 1026

14-80
Alternative Boot Operation for eMMC Card Devices
Figure 14-18: Flow for eMMC Alternative Boot Operation
expect_boot_ack = 1
No Start
Pattern
Step 14.a
1. The software driver checks:
• If the eMMC card device supports alternative boot operation (the BOOT_INFO bit is set to 1 in the
eMMC card).
• The BOOT_SIZE_MULT and BOOT_BUS_WIDTH values in the card device to use during the
boot process.
2. The software sets the following bits:
• Sets masks for interrupts by resetting the appropriate bits to 0 in the
• Sets the
Note: Altera recommends writing 0xFFFFFFFF to the
3. If the software driver needs to use the internal DMA controller to transfer the boot data received, it
must perform the following actions:
• Set up the descriptors as described in Internal DMA Controller Transmission Sequences and Internal
DMA Controller Reception Sequences.
• Set the use internal DMAC bit (
4. Set the card device frequency to 400 kHz using the
Clock Setup. Ensure that the card clock is running.
Altera Corporation
Step 13
Start Pattern & No
Boot Data Received
Step 14.b
Successfully
Received Boot
Data (14.d)
†
†
†
bit of the
int_enable ctrl
any pending interrupts before setting the
mode, the software driver needs to unmask all the relevant fields in the
†
Start
Step 1
Step 2 to Step 12
Start Pattern &
Boot Data Received
Step 14.e
NAC Timeout
Step 14.h
Stop
†
register to 1. Other bits in the
rintsts
int_enable
†
†
) of the
use_internal_dmac
registers. For more information, refer to
clkdiv
†
expect_boot_ack = 0
Step 15
No Boot Data Boot Data
Received Received
Step 16.a Step 16.b
Successfully
Received Boot
Data (16.d)
register.
intmask
register must be set to 0.
ctrl
register and register to clear
idsts
bit. For internal DMA controller
idinten
†
register to 1.
ctrl
SD/MMC Controller
cv_5v4
2016.10.28
†
†
†
register.
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