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OSD3358-SM-RED
– User Guide
Rev. 1.0 9/19/2017
Octavo Systems LLC
Copyright 2017
4.9
eMMC
Figure 49: OSD3358-SM-RED eMMC circuit
Figure 49 shows eMMC U7 connected to the processor through MMC1 interface. As discussed
in section 3.5, eMMC is the primary boot source for the processor. The Linux kernel and file
system needed to boot Linux are stored in here. The ROM code reads the second stage
bootloader in the eMMC and passes control to it. The ROM only supports 4 bit mode. But, after
initial boot, the eMMC can be interfaced in 8 bit mode. MMC1_CLK is the clock input and
MMC1_CMD is the command input to the eMMC. Pull up resistors are used on all the signals to
increase rise time on the signals and compensate for any capacitance on the board. More
information on booting of the board and board software can be found in Section 5.
