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SD Card Boot

SD Card boot is supported in Toradex bootloader V3.6b1 onwards.

To boot or update a Windows CE image from an SD Card, the following requirements should be met:

  • SDCard FAT16 formatted.
  • SDHC is not supported.
  • Image has to be located in the root folder.
  • Image has to be named "nk.bin"

To enable the SD Card boot, you have to edit the Config Block

boot.dltype=2           (Download via: 0=Ethernet,1=USBC,2=SDCard)

When selecting 'd' in the Bootloader Menu, the Windows CE image is loaded into RAM and the bootloader jumps to this image.

When selecting 'f' in the Bootloader Menu, the Windows CE image is saved to Flash first and is launched afterwards.

Configure SD GPIOs

If the SD card interface is conected to different GPIOs, other than on our Evaluation Board, you need to adjust the bootloader settings in order to use the SD card boot feature. The following settings need to be configured:

sd.clkgpio             GPIO used as SD CLK
sd.cmdgpio GPIO used as SD CMD
sd.dat0gpio GPIO used as SD DAT0
sd.dat1gpio GPIO used as SD DAT1
sd.dat2gpio GPIO used as SD DAT2
sd.dat3gpio GPIO used as SD DAT3
sd.cdgpio GPIO used as SD Card-Detect
sd.cdpol Polarity of Card Detect. 0=ActiveLow, 1=ActiveHigh
sd.drive Drive Strength (0..7) of SDcard pins
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