Before following the instructions in this section, user must have access to the switch console. User's terminal emulation software has to be configured with the following settings to ensure a successful console connection to the switch:
- Baud rate: 115200
- Data bits: 8
- Stop bits: 1
Modifying U-Boot Parameters
U-Boot (Universal Boot Loader) is an open source, primary boot loader for embedded devices. U-boot is used to package the instructions to boot the operating system kernel of a device. The following example shows the auto boot-up sequence:
U-Boot 1.3.0 (Sep 8 2014 - 16:39:03) CPU: 8541, Version: 1.1, (0x80720011) Core: E500, Version: 2.4, (0x80200020) Clock Configuration: CPU: 825 MHz, CCB: 330 MHz, DDR: 165 MHz, LBC: 41 MHz L1: D-cache 32 kB enabled I-cache 32 kB enabled I2C: ready DRAM: Initializing initdram robin1 initdram robin2 robin before CFG_READ_SPD robin after CFG_READ_SPD initdram robin3 DDR: 512 MB FLASH: 32 MB L2 cache 256KB: enabled In: serial Out: serial Err: serial Net: TSEC0, TSEC1 IDE: Bus 0: OK Device 0: Model: CF 512MB Firm: 20060911 Ser#: TSS25016070309051750 Type: Hard Disk Capacity: 495.1 MB = 0.4 GB (1014048 x 512) Hit any key to stop autoboot: 5
To modify the baud rate or other boot parameters, interrupt the boot sequence by hitting any key during auto boot. Once the boot sequence is interrupted, user is at the U-boot shell.
Do not interrupt the default auto boot sequence unless the file system is being fixed or the console port settings are being changed.
The most common commands in U-Boot are:
- help - Get command line help.
- printenv - Show all environment variables. The U-Boot environment is a block of memory kept on persistent storage and copied to RAM when U-Boot starts. It stores environment variables used to configure the system.
- version - Show the U-Boot version.
- setenv - Set an environment variable.
- saveenv - Save the modification in the environment memory.
Use the set and save commands to reset the U-Boot environment variables. In the example below, the baud rate is set to 11520 with the setenv baudrate 115200 command.
=> set baudrate 115200 => save Saving Environment to Flash... Un-Protected 1 sectors Erasing Flash... . done Erased 1 sectors Writing to Flash... done Protected 1 sectors => reset
PicOS switches do support Linux shutdown command. To shut down a switch, after running the “sudo shutdown -h now" command, disconnect the power supply.