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The Emcraft STM32MP1 Starter Kit supports several boot devices. Selection of a specific boot device is defined by the state of the jumpers on the JP10 header of STM32MP1-BSB and switches on the SOM-BSB development board, as described in the following sectionssection.
1. Selecting Boot Device on STM32MP1-BSB
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State ON means presence of a jumper on the corresponding pin of the JP10 header; state OFF means absence of a jumper.
2. Selecting Boot Device on SOM-BSB
Selection of a specific boot device is defined by the state of the switches on the SOM-BSB development board, as follows:
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SW4.2
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SW4.3
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Boot from SD Card
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-
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OFF
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ON
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Boot from on-module eMMC
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-
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ON
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OFF
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Boot from USB Serial Downloader
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-
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OFF
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Boot in Debug engineering mode
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OFF
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ON
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ON
2.1. Hardware Modifications for Boot in Debug Engineering Mode
Connect a 1k...3.3k resistor between +3.3V and S4 pin 2 (S4.2). The closest +3.3V points are the following:
U8.1 = C18.2
R16.2 (the farthest pin from S4)
Connect with a wire S4.2 to P2.1.
By default, the Starter Kit is configured to boot the default Linux configuration from the on-module eMMC. You can override this configuration by modifying the set of the switches on the SLX-SOM-BSB, as described above.
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