beaglebone-black - Flipbook - Page 32
BeagleBone Black
• Serial BooT: This mode will use the serial port to allow downloading of the software direct. A separate
USB to serial cable is required to use this port.
• USB Boot: This mode supports booting over the USB port.
Software to support USB and serial boot modes is not provided by beagleboard.org.Please contact TI for support
of this feature.
A switch is provided to allow switching between the modes.
• Holding the boot switch down during a removal and reapplication of power without a microSD card inserted will force the boot source to be the USB port and if nothing is detected on the USB client port, it
will go to the serial port for download.
• Without holding the switch, the board will boot try to boot from the eMMC. If it is empty, then it will try
booting from the microSD slot, followed by the serial port, and then the USB port.
• If you hold the boot switch down during the removal and reapplication of power to the board, and you
have a microSD card inserted with a bootable image, the board will boot from the microSD card.
NOTE: Pressing the RESET button on the board will NOT result in a change of the_ _boot mode. You MUST
remove power and reapply power to change the boot mode.The boot pins are sampled during power on reset
from the PMIC to the processor.The reset button on the board is a warm reset only and will not force a boot
mode change.
5.4 Power Management
The TPS65217C power management device is used along with a separate LDO to provide power to the system.
The**TPS65217C** version provides for the proper voltages required for the DDR3L. This is the same device
as used on the original BeagleBone with the exception of the power rail con昀椀guration settings which will be
changed in the internal EEPROM to the TPS65217C to support the new voltages.
DDR3L requires 1.5V instead of 1.8V on the DDR2 as is the case on the original BeagleBone. The 1.8V regulator
setting has been changed to 1.5V for the DDR3L. The LDO3 3.3V rail has been changed to 1.8V to support those
rails on the processor. LDO4 is still 3.3V for the 3.3V rails on the processor. An external LDOTLV70233 provides
the 3.3V rail for the rest of the board.
5.4.1 PC USB Interface
The board has a miniUSB connector that connects the USB0 port to the processor. This is the same connector
as used on the original BeagleBone.
5.4.2 Serial Debug Port
Serial debug is provided via UART0 on the processor via a single 1x6 pin header. In order to use the interface
a USB to TTL adapter will be required. The header is compatible with the one provided by FTDI and can
be purchased for about $$12 to $$20 from various sources. Signals supported are TX and RX. None of the
handshake signals are supported.
5.4.3 USB1 Host Port
On the board is a single USB Type A female connector with full LS/FS/HS Host support that connects to USB1 on
the processor. The port can provide power on/o昀昀 control and up to 500mA of current at 5V. Under USB power,
the board will not be able to supply the full 500mA, but should be su昀케cient to supply enough current for a
lower power USB device supplying power between 50 to 100mA.
You can use a wireless keyboard/mouse con昀椀guration or you can add a HUB for standard keyboard and mouse
interfacing.
5.4. Power Management
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