[讨论] BB Black 启动模式

英蓓特提供的资料太少，没办法，找了点分享出来： there are four boot modes: 四种引导模式：  eMMC Boot…This is the default boot mode and will allow for the fastest boot time and will enable the board to boot out of the box using the pre-flashed OS image without having to purchase an microSD card or an microSD card writer. eMMC引导：这是默认启动模式，启动时间最短。不需要一个含有OS镜像的TF卡，也不需要购买TF卡以及读卡器  SD Boot…This mode will boot from the microSD slot. This mode can be used to override what is on the eMMC device and can be used to program the eMMC when used in the manufacturing process or for field updates. SD引导：此模式将从TF卡插槽引导开机。这个模式可以用来重写eMMC。再生产或者现场更新时，可用来升级eMMC。  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. 串口引导模式：这个模式可以利用串口直接下载软件。需要准备一个USB转TTL的线。  USB Boot…This mode supports booting over the USB port. USB引导模式：这个模式支持通过USB口引导。 Software to support USB and serial boot modes is not provided by beagleboard.org. Please contact TI for support of this feature. Beagleboard.org不提供支持串口和USB引导的软件。请联系TI获取响应的支持。 本帖最后由 azhiking 于 2014-3-6 15:32 编辑

A switch is provided to allow switching between the modes.
可以通过一个开关来切换引导模式。

 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.
断电情况下按住BOOT按钮，重新上电会，如果没有TF卡插入，会强制从USB口引导，如果USB口不能引导，会从串口引导。

 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.
如果没有按住BOOT按钮 ，板子会按照eMMC->TF卡->串口->USB口的顺序进行引导。

 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.
如果按住BOOT按钮重新上电，并且插有含有可启动映像的TF卡的话，会从TF卡引导。

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.
注：按主板上的RESET按钮，将不会导致引导模式的改变。必须切断电源并重新接通电源来更改引导模式。启动引脚上电时采样上电复位从PMIC到处理器。电路板上的复位按钮只有一个热复位并不会强制引导模式转变。

有不当的地方欢迎拍砖指正，谢谢！

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.
如果按住BOOT按钮重新上电，并且插有含有可启动映像的TF卡的话，会从TF卡引导。

这一条，按住boot键上电，从sd卡启动还是对emmc更新系统？

不拍 围观

BB-Black更新系统是一直按住uSD BOOT按钮吗？