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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html><head> <title></title> <link rel="stylesheet" media="screen" type="text/css" href="./style.css" /> <link rel="stylesheet" media="screen" type="text/css" href="./design.css" /> <link rel="stylesheet" media="print" type="text/css" href="./print.css" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head><body><a href=start.html>start</a></br><div class="toc"><div class="tocheader toctoggle" id="toc__header">Table of Contents</div><div id="toc__inside"><ul class="toc"><li class="clear"><ul class="toc"><li class="level2"><div class="li"><span class="li"><a href="#u-boot_features" class="toc">U-Boot Features</a></span></div><ul class="toc"><li class="level3"><div class="li"><span class="li"><a href="#overview_of_of_uboot_s_features" class="toc">Overview of of U鈥態oot's features:</a></span></div></li><li class="level3"><div class="li"><span class="li"><a href="#u-boot_commands" class="toc">U-boot commands</a></span></div></li></ul></li></ul></li></ul></div></div><h2><a name="u-boot_features" id="u-boot_features">U-Boot Features</a></h2><div class="level2"><p>U鈥態oot is a boot loader program that is stored in flash memory on the target system. U鈥態oot allows the target to load an ELF memory image from a serial connection, a network connection, or flash memory. When U鈥態oot is stored in flash memory on the target system it can be loaded on system reset, U鈥態oot can then obtain a uClinux memory image and boot uClinux. </p></div><!-- SECTION [1-400] --><h3><a name="overview_of_of_uboot_s_features" id="overview_of_of_uboot_s_features">Overview of of U鈥態oot's features:</a></h3><div class="level3"><ul><li class="level1"><div class="li"> <strong>Autoboot</strong> - Autoboot will automatically boot the system on power up or reset of the board after the timer counts down. The countdown timer is setup with a default time of 30 seconds. If a key is pressed before this time the autoboot procedure halts and the user is brought to the U鈥態oot command line.</div></li><li class="level1"><div class="li"> <strong><acronym title="Operating System">OS</acronym> Loading Commands</strong> - A number of <acronym title="Operating System">OS</acronym> loading commands are available that can be executed from the U-Boot command line. Commands such as <strong>boot</strong>, <strong>bootelf</strong>, <strong>bootp</strong>, and <strong>loadb</strong> are available to load various file types.</div></li><li class="level1"><div class="li"> <strong>Upgrade Features</strong> - U鈥態oot allows itself to be upgraded with a new version from within U鈥態oot. JTAG or ICE connection are not necessary in this case. See <a href="upgrading_u-boot.html" class="wikilink1" title="upgrading_u-boot.html">upgrading_u-boot</a>.</div></li><li class="level1"><div class="li"> <strong>Networking</strong> - U鈥態oot has support for the common network commands <strong>ping</strong>, <strong>tftp</strong>, and <strong>dhcp</strong>. See <a href="setting_up_a_tftp_server.html" class="wikilink1" title="setting_up_a_tftp_server.html">setting_up_a_tftp_server</a> and <a href="setting_up_a_dhcp_server.html" class="wikilink1" title="setting_up_a_dhcp_server.html">setting_up_a_dhcp_server</a> for aditional infomation.</div></li><li class="level1"><div class="li"> <strong>Environment Variables</strong> - Environment variables can be set, saved, and displayed through the U鈥態oot command line using the commands <strong>setenv</strong><strong> </strong>or<strong> set</strong>, <strong>save</strong> or <strong>saveenv</strong>, and <strong>print</strong> or <strong>printenv</strong>.</div></li><li class="level1"><div class="li"> <strong>Serial downoading of an Image</strong> - A memory image can be downloaded through the serial port onto the target system. See <a href="loading_dxes_via_the_serial_port.html" class="wikilink1" title="loading_dxes_via_the_serial_port.html">loading_dxes_via_the_serial_port</a>.</div></li><li class="level1"><div class="li"> <strong>Reading MAC Address From EEPROM</strong> - U鈥態oot allows for automatic reading of the MAC address from the target’s EEPROM. The MAC Address can be set one of two ways, in U-Boot using the environment variable <em>ethaddr</em>, or it can be loaded from external EEPROM. On reset/power up of the SMC91C111 the MAC address is read from EEPROM and is stored in its internal registers. When the network command is executed in U鈥態oot the environment variable <em>ethaddr</em> is checked. If there is a valid MAC address set in this variable then it takes precedence over the EEPROM value and is stored in the SMC’s internal registers. This is a useful feature because U鈥態oot has the ability to pass MAC address to another application (e.g. uClinux). Once <em>ethaddr</em> is set it can only be changed by re-flashing U鈥態oot onto the target.</div></li><li class="level1"><div class="li"> <strong>Booting U-boot from parallel or serail flash</strong> - U-boot can be configured to boot either from parallel NOR flash or serial (4-wire SPI-compatiable interface) NOR flash devices. Refer to <a href="compiling_u-boot.html" class="wikilink1" title="compiling_u-boot.html">compiling_u-boot</a> and <a href="loading_u-boot.html" class="wikilink1" title="loading_u-boot.html">loading_u-boot</a>. Specially, for BF537, you can <a href="loading_u-boot.html#bf537_loading_u-boot_from_uart" class="wikilink1" title="loading_u-boot.html">load and boot U-boot from UART</a>.</div></li><li class="level1"><div class="li"> <strong>Accessing different memory devices</strong> - In U-boot different memory devices are supported. including parallel NOR flash, <a href="accessing_serial_nor_flash_with_u-boot.html" class="wikilink1" title="accessing_serial_nor_flash_with_u-boot.html">serial NOR FLASH</a>, <a href="using_nand_flash_with_u-boot_and_linux_kernel.html" class="wikilink1" title="using_nand_flash_with_u-boot_and_linux_kernel.html">NAND flash</a> and <a href="using_cf_flash_card_disk_with_uboot_and_linux_kernel.html" class="wikilink1" title="using_cf_flash_card_disk_with_uboot_and_linux_kernel.html">CF card.</a> </div></li></ul></div><!-- SECTION [401-3269] --><h3><a name="u-boot_commands" id="u-boot_commands">U-boot commands</a></h3><div class="level3"><p> The following is an imcomplete list of available commands that can be executed from the U鈥態oot command line. The supported commands may be different for different configurations and versions. Please refer to <a href="compiling_u-boot.html" class="wikilink1" title="compiling_u-boot.html">compiling_u-boot</a>. This list can be displayed within U鈥態oot by executing the <strong>help</strong> command. </p><pre class="code">stamp> help? - alias for 'help'autoscr - run script from memorybase - print or set address offsetbdinfo - print Board Info structureboot - boot default, i.e., run 'bootcmd'bootd - boot default, i.e., run 'bootcmd'bootelf - Boot from an ELF image in memorybootm - boot application image from memorybootp - boot image via network using BootP/TFTP protocolbootvx - Boot vxWorks from an ELF imagecmp - memory compareconinfo - print console devices and informationcp - memory copycrc32 - checksum calculationdate - get/set/reset date & timedcache - enable or disable data cachedhcp - invoke DHCP client to obtain IP/boot paramsecho - echo args to consoleeeprom - EEPROM sub-systemerase - erase FLASH memoryflinfo - print FLASH memory informationfsinfo - print information about filesystemsfsload - load binary file from a filesystem imagego - start application at address 'addr'help - print online helpicache - enable or disable instruction cacheicrc32 - checksum calculationiloop - infinite loop on address rangeimd - i2c memory displayiminfo - print header information for application imageimls - list all images found in flashimm - i2c memory modify (auto-incrementing)imw - memory write (fill)inm - memory modify (constant address)iprobe - probe to discover valid I2C chip addressesitest - return true/false on integer compareloadb - load binary file over serial line (kermit mode)loads - load S-Record file over serial lineloop - infinite loop on address rangels - list files in a directory (default /)md - memory displaymm - memory modify (auto-incrementing)mtest - simple RAM testmw - memory write (fill)nfs - boot image via network using NFS protocolnm - memory modify (constant address)ping - send ICMP ECHO_REQUEST to network hostprintenv- print environment variablesprotect - enable or disable FLASH write protectionrarpboot- boot image via network using RARP/TFTP protocolreset - Perform RESET of the CPUrun - run commands in an environment variablesaveenv - save environment variables to persistent storagesetenv - set environment variablessleep - delay execution for some timetftpboot- boot image via network using TFTP protocolversion - print monitor version</pre></div><!-- SECTION [3270-] --></body></html>⌨️ 快捷键说明
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