The Boot Mode, or sometimes called Download Mode, is necessary to change the operating system on your board. In this mode you’re able to flash the eMMC or NAND.
The 3 bootmode pins are located next to the RGB display output. With the jumper the bootmode can be pulled to high (H) or low (L).
To enable the bootmode connect the two pins for L with the jumper.
For normal boot, please check that the bootmode jumper is on H.
To bring your device into Boot Mode, place a jumper to connect the Boot Mode pins.
For normal boot, please check that the bootmode jumper is open.
JP1 is used to configure the boot mode and the JTAG topology.
There is only one JTAG on the chip, and two JTAG modes are supported. Between these modes is selected via the JTAG_MOD pin:
|Debug mode||0||DAP is the only TAP controller in the daisy chain. SJC will be attached to JTAG-AP of DAP.|
|Test mode||1||SJC is the only TAP controller in the daisy chain. 1149.1-compliant, and support 1149.6 AC coupled test.|
Do not touch the test mode pin!