3.5.6 Disable Boot
On-board push button SW4 and/or jumper J22 control the selection (CS#) of the bootable memory components, QSPI and e.MMC NAND Flash, using a non-inverting 3-state buffer for the first memory and a MOSFET for the second one.
The rule of operation is:
- SW4 (DISABLE_BOOT) or J22 shorted: booting from QSPI and e.MMC NAND FLASH is disabled.
- LED D8 indicates the state of the DIS_BOOT signal:
- Red: the on-board boot memories are disabled.
- Green: the on-board boot memories are enabled.
Note: The “Disable Boot” mechanism does
not disable booting from SD Card connector J4. The user must remove the SD Card to
disable booting from it.