GSG: Booting the OMAP-L138/AM18x Out of the Box
By default, DA850/OMAP-L138/AM18x EVM comes up with CPU operating at 300MHz. With earlier PSP releases (03.20 and 03.21) UBL has to be re-built to boot at a higher CPU frequency. You can also use the Linux CPUFreq driver to change the operating point after Linux has booted up. With latest PSP release (03.22) CPU frequency can be modified only from Linux.
Booting the EVM
NOTE: The EVM (beta version and later) is configured at manufacturing to allow the board to boot up Linux out of the box without having to build or install any additional software. For earlier versions of EVM (alpha or pre-alpha), user still needs to flash U-Boot and UBL to flash. Please refer to the topic on flashing the boot images.
Use the following steps to boot the board:
- Refer to the usage information available on LogicPD website.
- Make sure that the SOM module is properly plugged into the EVM baseboard.
- Connect the serial cable included with the kit to the serial port of the EVM board and connect the other end to the serial port of a workstation.
- Make sure the the boot switch pins on switch S7 are in the correct position:
S7:8 (BOOT) S7:7 (BOOT) S7:6 (BOOT) S7:5 (BOOT) OFF OFF OFF OFF
- Run a terminal session on your workstation and configure it to connect to the serial port with the following settings
- Bits per second: 115,200
- Data bits: 8
- Parity: None
- Stop bits: 1
- Flow control: None
- Transmit delay: 0 msec/char, 100 msec/line
- Upon powering up the board, you should see U-Boot start up and then messages indicating that the Linux kernel is starting up. When the boot sequence has completed, you should see a login prompt.
Initial kits that ship may power up to a U-Boot prompt rather than automatically boot Linux. If you have such a kit, you will need to set up U-Boot to boot Linux.
- Log in as root (no password).
- At the Linux prompt, you can use existing Linux commands to test various features and use examples from the "examples" folder under the "images" directory.
- While U-Boot is booting, you can press any key to interrupt the automatic boot of the Linux kernel. This will leave you in U-Boot, where you can type commands in the U-Boot command shell.
NOTE: The AM18x EVM / eXperimenter’s Kit comes with a demo that should boot out of the box according to the instructions in this video. If you changed the u-boot default environmental variables and want to restore them, please follow the instructions on this page or use the following u-boot commands to set them:
- setenv bootcmd 'sf probe 0;sf read 0xc0700000 0x80000 0x220000;bootm 0xc0700000'
- setenv bootargs mem=32M console=ttyS2,115200n8 root=/dev/mmcblk0p1 rw rootdelay=3 ip=off
- setenv bootfile "uImage"