User's Manual
Contents
1. ETHERNET interface CS8900 ethO ETHERNET interface CS8900 eth1 FPROM and CPLD programming optional 16 pin JTAG pin header for initial Figure 2 Block diagram of the version 1 miniLIAB The miniLIAB board comprises the following features e Microprocessor with an Intel 80386 compatible CPU core running at 25 MHz The processor includes interrupt and DMA controllers timers and general purpose digital I O ports e 16 MB DRAM e 8 MB nonvolatile FLASH PROM memory e One or two 10 Mbit Twisted Pair 10Base T Ethernet connections One Ethernet connection is optional and can be replaced by three general purpose LED s with drivers e Two asynchronous serial lines one with a RS232 line driver miniLIAB User s Manual 9 e A 64 pin connector giving access to the data address and con trol signals of the CPU bus together with pins for interrupts and two eight bit general purpose digital I O ports The pinout of JP4 of the miniLIAB is similar to the pinout of the 64 pin connector of another Intel 386EX based LIAB board denoted LIAB Classic This means that extension boards for the LIAB Classic will work with the miniLIAB as well and vice versa You should however be aware of one considerable difference between the two boards The Classic boards power supply pins of the 64 pins connector are 5 volts while the 64 pins connector of the miniLIAB can be selected to either 3 3 volts or the2. 0x0280 IRQ 14 EEPROM present and checksum of the EEPROM readout was OK Linux version 2 4 17 smm ris gcc version 2 95 4 20011002 Debian prerelease 14 Thu Aug 29 11 43 00 CEST 2002 BIOS provided physical RAM map BIOS 88 0000000000000000 000000000009f000 usable BIOS 88 0000000000100000 0000000001000000 usable On node 0 totalpages 4096 16 miniLIAB User s Manual zone 0 4096 pages zone 1 O pages zone 2 O pages Kernel command line noinitrd no hlt root 1f00 ro liabIP 192 168 1 180 8 192 168 1 1 liabHOST liab liab dk ether 8 380 eth0 ether 14 280 eth1l Initializing CPU 0 Calibrating delay loop 3 44 BogoMIPS Memory 14408k 16384k available 880k kernel code 1588k reserved 196k data 48k init Ok highmem After approximately 45 seconds you will get a Linux login prompt where you can login as users root or liab The passwords are supplied on a separate piece of paper in the shipment from LIAB Electronics ApS miniLIAB User s Manual 17 4 The Boot Loader The boot loader represents the very first code executed after a power up or reset of the i386EX microprocessor The flow of the boot loader is shown in Fig 6 The 1386EX processor starts executing instructions in a native 8086 mode from address 0xfffffff0 At this address which constitutes the top 16 bytes of the FPROM a long jump to address 0x00000000 is performed Next instructions ar
3. home usr share and usr local directo ries Finally liabdisc ramvartmp contains the contents of var and tmp Though it requires some knowledge to make modications in the proper places building a new disc image is straight forward Running the script mk fpromimage located in 1iabdisc builds compressed images of the four ramdisc copies them to the Images directory of the root file system and finally makes a disc image of the root file system The mkdisc script in the liabboot directory makes a uuencoded version of the disc image which is suitable for downloading to the miniLIAB using the cu terminal emulator see App A 6 3 Modifications on Target The process of making modifications using the development kit is very similar to the process for LIAB platforms without MTD support With the introduction of the miniLIAB 4C distribution it is however possible to make modifications direcly on target This can be very useful since it enables the possibility for remote updates Furthermore updates can be performed much faster since the full disc images does not have to be upload at 115 kbaud for every little change The process of making modifications on target has many advantages but it is very complicated and special care must be taken to avoid corruption of the root file system To simplify the process the distribution includes six different scripts that can perform the basic operations such as write enabling the FPROM or building
4. r lt rate gt Set baudrate 0 9600 1 19200 2 34800 3 57600 4 115200 s Scan memory for GZIP images x lt addr gt Load data to RAM starting at address lt addr gt using the XMODEM protocol with simple checksum 2 lt src gt lt dst gt Decompress GZIP image at lt src gt into lt dst gt items marked with give access to submenues Boot gt From the Boot gt prompt enter the parameter submenu by typing the p com mand Help in both submenus can be obtained using the h command Boot gt p Entering the boot network parameter editor h for help use options n and a for editing of network stuff Param gt h a alter the network specifications h help this text d lt line gt delete the specified parameter line i lt line gt lt param gt insert text lt param gt before parameter line lt line NOTE the text string must NOT contain spaces n show the network specifications P print the boot network parameters q quit boot network parameter submenu W write new parameters back to FPROM aram gt 20 miniLIAB User s Manual When shipped from LIAB Electronics ApS the LIAB is configured with a set of default parameters that can be view using the p command Param gt p 1 noinitrd 2 no hlt 3 root 1f00 4 ro 5 liabIP 192 168 1 180 8 192 168 1 1 6 liabHOST liab liab dk Param gt The first four parameters are all essential for booting the LIAB with the current di
5. 8 192 168 1 1 liabIP2 192 168 2 10 8 192 168 1 1 7 lLiabHOST liab dummy Param gt w NOs WN Do you want to write the parameters back to FPROM y n gt y Boot parameters start at 0x007ff800 Param gt You are now ready to boot the Linux system Either you press the reset button SW1 or you enter two q quit commands Param gt q Boot gt q DRAM size in Mbytes 16 Scanning FPROM memory range 0x00000000 to Ox007ffffFf You will now observe a boot sequence similar to the one printed on page 15 Even tually you will get a login prompt where you can login as users root or Liab The passwords will be supplied on a separate piece of paper You may also connect to the LIAB using telnet and you should consider trying to browse the home page on the LIAB using e g net scape 22 miniLIAB User s Manual 4 5 Download of Binary Images To download binary images over the serial port you face the problem that most serial drives are unable to receive and transmit all the 256 possible ASCII char acters 0x00 to 0xff A simple way to solve the problem is to chop the stream of bits into chunks of six bits With a proper offset these chunks can now be send using the alphanumeric part of the ASCII codes Other characters can be used to signal start of line end of line etc For this purpose an utility called uuencode is readily at hand in typical Unix or Linux systems Traditionally the first line of a uuenc
6. Center pin positive ed To suitable wall EA be plugin power unit P1 or transformer sm Lp with fuse Serial connection between LIAB and host PC To COM port on host PC 10 Mb Ethernet lt a EE TER A P4 network card in PC 10 Mb Ethernet lt a EEE P3 Latter case Tx Rx pairs must be crossed Figure 4 Connections to the exterior world power serial port and network you may connect the board to a 10 Mb Ethernet network using the RJ45 connector P3 The four mentioned connections to the exterior world are shown in Fig 4 A suitable serial cable can be purchased in a well stocked computer shop Alterna tively you can make one yourself if you have at hand two female DB 9 connectors and a length of cable with three wires The wiring you need to make is shown in Fig 5 Serial connection between LIAB and host PC DB 9 female DB 9 female rear view rear view 5 49 To COM port 3 8 To COM port on LIAB 2 7 on HOST PC 6 1 Figure 5 Serial communication for the LIAB connectors and wiring diagram miniLIAB User s Manual 15 3 3 Start a Terminal Emulator and Apply Power Having connected the LIAB board to your host computer using the serial cable you are ready to apply power through power connector P1 A terminal emulator on the host computer must be started and configured for 9600 baud 8 databits and no parity bit On a PC running Linux you may use the terminal program cu as describ
7. a new ramdisc image The scripts are described in Table 3 Though these scripts are a big help a good understanding of the concepts of the file system is still necessary in order to make the right changes and run the right scripts 30 miniLIAB User s Manual flash rw This script remounts the root file system to a writeable state After running this script persistent modifications can be made to all the directories residing in the FPROM Note that because of the buffer cache in the linux kernel such modification will not necessarily be written to the FPROM immediately flash ro To ensure that modifications in the buffer cache are cor rectly flushed to the FPROM the root file system should be remouted to the read only state using this script Note that this script will usually run for several seconds since it waits for the actual FPROM write operations to be completed mkUsergz After making changes to any of the directories lo cated in the ramdisc that is mounted at ramuser the roothomelocal ramdisc this script can be run to make the changes persistent mkDevgz After making changes in dev this script can be used to make te changes persistent by building a new com pressed ramdisc image and placing it in the correct loca tion in Images mkEtcgzl It is a little bit more complicated to make modifications to the configuration files in etc because some of the files are modified during the boot process This script ca
8. access the JTAG interface you need the JTAG adaptor see the enclosed CD ROM for schematics and PCB for the JTAG adaptor The JTAG adaptor must be connected to the parallel port of the host PC using a standard parallel cable On the CD ROM you will also find a JTAG program that will enable you to access the FLASH PROM and upload software JP2 also provides a JTAG interface to the CPLD U5 to be able to program the device To access the XILINX CPLD you need a special JTAG device Please consult the Xilinx homepage for more information
9. as root and create the file rhosts in this way root liab cat gt rhosts lt host PC s IP number gt lt userid gt lt Ctrl D gt root liab With the rhosts file in place you can transfer the file hello to the LIAB using the following command rcp hello root lt LIAB s IP number gt The file hello is now copied to root s home directory root on the LIAB and can be executed by simply typing hello root liab hello Hello LIAB root liab As expected the text string Hello LIAB is also printed when the application is executed on the LIAB When the application is finished and tested on both the PC and the LIAB it can be saved in the FPROM on the LIAB so it is available after the LIAB has been reset This should be done by following the procedures in either section 6 2 or section 6 3 7 2 Accessing Hardware The previous example was able to run on both the PC and the LIAB as it does not depend on any specific hardware If you want to develop an application for the LIAB that makes direct access to the hardware for example the two 8 bit general purpose I O ports available at the JP4 connector you can nolonger test everything on the PC However you still have the advantage that all the development tools are identical The development kit also includes an example of an application that makes di rect hardware access In the software liabuserspace demos directory you will find a file 1e
10. de he A 35 References 37 Appendices 38 A Using cu as Terminal Emulator 38 B The JTAG Interface 39 miniLIAB User s Manual 5 1 Introduction The Linux In A Box LIAB for short project was started in the summer of 1998 at the Institute of Electromagnetics Systems at the Technical University of Denmark DTU The aim was to develop a small microprocessor board feasible of performing control and data aquisition task in relation to an antenna measurement facility A prototype and the first generation of the LIAB board were developed at DTU In the fall of 2000 all activities were moved to the Danish company LIAB Elec tronics ApS a company focused on developing single board computers based on the Linux operating system All parts of the hardware and the bootloader are copyright of LIAB Electronics ApS the rest of the software are copyright of the respective holders However all hardware and software are open sourced For the hardware this means that ev erybody gains full insight in all schematics and PCB designs Similarly everybody have full insight in the source code for the bootloader patches for the Linux kernel and images for the file system You are free to distribute the full documentation of the hardware and source codes of software If you make changes to either parts you must clearly mark which parts are yours and which are part of the original distributions from LIAB Electronics ApS If you sell a product that uses the LIAB b
11. these are replaced by the real version that are located in the ramdisc images In the etc directory there are two important files that are used in the first part of the 28 root Images bin lib security mnt miniLIAB User s Manual dev ram3 Sre RamdiscDevimage gz Size 500 KB dev ram2 Src RamdiscEtclmage gz Size 500 KB miniLIAB FLASH disk under mtd normally mounted read only proc sbin Indicates a ramdisc usr arch l 1 Initialized using a gzip ed bin __ image from Images lib sbin local dev ram5 iscRoot home Te Psy Size 3000 KB root liab mntpoint ramuser var lo dev ram4 9 Src RamdiscVar gz run Size 1000 KB mntpoint ramvar Figure 7 The miniLIAB file system miniLIAB User s Manual 29 boot process and are consequently found in the initial version of the et c directory located in liabdisc libc6 etc The first file is the inittab file which describes which programs should be automatically started The second is the rc sysinit file which is the script that decompresses and mounts the ramdisc images Ex cept these two files all modifications to the etc directories should be made in the liabdisc rametc directory Similarly modifications to dev of the miniLIAB should be made to the directory liabdisc ramdev on the PC The liabdisc ramroothomelocal directory con tains the contents of the root
12. will be printed Please Note As of release 4C it is possible to transfer binary data using the Xmodem protocol as implemented in some terminal emulators e g MiniCom on Linux and HyperTerminal on Microsoft Windows The new approach has the advantage that data is transfered in 8 bit which makes it significantly faster than transfer of uuencoded data However there are also 24 miniLIAB User s Manual some disadvantages to data transfer using the Xmodem protocol The raw file does not include the intended target address and thus it must be set by the user This is a new source of errors Also the Xmodem protocol always transfers the file in chucks of 128 bytes resulting in some extra bytes being written to RAM or PROM Regardless of whether you are in the main menu or the Flash PROM submenu you can start the download using the x command This will make the LIAB listen for incoming Xmodem data Next you need to start sending the file In HyperTerminal this is done from one of the menus PROM gt x 10000 MODEM Ready to receive data please start your transmitter se an ASCII CAN 0x18 ctrl X to terminate reception manually MODEM Received 525568 bytes MODEM No errors encounted PROM gt Hx x GG x ta miniLIAB User s Manual 25 5 The LIAB Development Kit A CD ROM is enclosed in the shipment from LIAB Electronics that contains docu mentation and software for the miniLIAB board The distribution is open sourced as des
13. 5 to 7 volts board supply power 2 1 Layout of the miniLIAB Board The electronics for the LIAB board is assembled on a four layer PCB with two layers for signals and two for power The dimensions of the PCB is 100x100 mm 4x4 inch and the weight is 80 grams All components are placed on one side of the PCB The layout of connectors jumpers and main components are shown in Fig 3 To the left the CPU and the 64 pin I O connector is located To the right connectors for power and external communication are located together with a reset button Four Pin Headers are present on the LIAB board JP1 to JP4 The purpose of the individual headers are described in Table 1 in section 2 2 The miniLIAB board must be powered by a regulated DC supply between 5 and 7 volts center pin positive and consumes about 2 watts The miniLIAB board has been tested to work from 15 C to 60 C 2 2 Pin Headers JP1 to JP4 Four pin headers are present on the miniLIAB board JP1 to JP4 Their location can be observed in Fig 3 and pin no 1 is marked with a crossed rectangle All pin headers consist of one or two rows of gold plated pins placed on a 100 mil 2 54 mm module grid except for JP2 which is placed on a 2 00 mm module The pin headers are feasible for mating PCB or ribbon cable connectors The purpose of the individual four pin headers are described in Table 1 Please consult the LIAB hardware reference 7 for the specific functions of the in
14. 996 ISBN 1 56592 151 8 38 miniLIAB User s Manual A Using cu as Terminal Emulator The miniLIAB board was specifically designed for the Linux operating system and a natural choice for a development platform and host computer would be a IBM compatible Personal Computer PC running Linux A number of terminal emula tors are readily available in the various Linux distributions or can be downloaded over the Internet One of the oldest and simplest emulators is the cu program which stands for Con nect Unix You don t get any fancy graphical user interface you just get connected In the following we assume that the LIAB board is connected to the COM1 port on the host PC and that this port can be accessed trough the device file named dev ttyS0 this is at least true for Redhat 5 x or later distributions To start cu log in as root and type the command cu 1 dev ttySO s 9600 To exit cu again type a tilde followed by a dot on a new line cu i dev ttySO s 9600 Connected lt communication with the LIAB board gt Disconnected It may be inconvenient to have to log in as root when using cu To access the COM1 port from any user account you have to change the permissions on the device files that refers to the COM ports chmod 666 dev ttys0 will give permissions to everybody to use the port Downloading kernel or disc images to the LIAB board can also be done from within cu If you want to download th
15. A as SE os R ue do POOOOOOOOOOON SO XX ESSE OOOO SKK KKK SOOO Linux In A Box User s Manual for the miniLIAB Microprocessor Board This document describes the use of the miniLIAB microproces sor board A brief introduction to the LIAB Linux In A Box board is given together with a description on how to get the microprocessor board up and running Please also consult the Linux In A Box hardware reference 7 All parts of the mini LIAB hardware and software is copyright of LIAB Electronics Aps LIAB Electronics ApS Industrimarken 2 DK 9530 St vring Denmark http www liab dk Document no UM0002 3 August 2002 2 miniLIAB User s Manual NOTICE The information in this document is subject to change without notice THE SOFTWARE AND DOCUMENTATION ARE PROVIDED AS IS WITH OUT WARRANTY OF ANY KIND INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PUR POSE FURTHER LIAB Electronics ApS DOES NOT GUARANTEE OR MAKE ANY REPRESENTATIONS REGARDING USE OR THE RESULT OF THE USE OF THE SOFTWARE HARDWARE OR WRITTEN MATERIAL IN TERMS OF CORRECTNESS ACCURACY RELIABILITY OR OTHERWISE This document pertains to the miniLIAB 4C distribution running on the revision 1 2 miniLIAB board Notice that some differences exists if you are using different versions of either software or hard ware miniLIAB User s Manual Contents 1 Introduction 1 1 Th
16. This is done with the e command In the default configura tion the bootloader is located from 0x0 to 0xffff the kernel from 0x10000 to Oxfffff and finally the disc image from 0x100000 to 0x77ffff The remain ing half megabyte is available for special application to use except the last sector which is reserved for the boot parameters If you want for instance want to down load a new kernel you should erase the needed sectors using the e command FPROM gt e 10000 fffff Start address cessa 03010000 End address usas css ah OXOELETE Block size Kbytes 960 Do you want to erase y n gt y FPROM gt Regardless of whether you are in the main menu or the Flash PROM submenu you can start the download using the 1 command This will make the LIAB listen for incoming uuencoded data Next you need to instruct your terminal emulator to start sending the file Assuming that you are using cu and that the uuencoded kernel is in the file v this is done using the following command as further described in Appendix A FPROM gt 1 gt V dic eSB Teapot 11679 11680 11681 11682 11683 file transfer complete connected No errors during reception of uuencoded data Start Address cuca psi ot 10000 End Address iu sacada esses 904fc LONGUS saem eed dot dp eed 525565 POSIX 1 CRC checksum 3977935324 FPROM gt If the transfer was not successful or the data could not be written to the FPROM an appropriate error message
17. a comment during the boot process To try the included example change to the 1iabadditional directory and run the script Notice that you must be the root user to run the script cd lt PathToLIABDevelopmentKit gt software liabadditional mkAdditionalExampleTarGz Creating tar file 36 miniLIAB User s Manual etc etc rc d etc rc d rc additional home home httpd home httpd html home httpd html index html tgz file additionalExample tar gz now created for the miniLIAB Copy the file to Images of the running LIAB e g using rcp Remember to use the flash rw and flash ro scripts to control the read write status of the FPROM Now follow the instructions in section 6 3 to write enable the FPROM before copy ing the additionalExample tar gz file to the Images directory You can copy the file using rcp or ftp as explained in section 7 1 To make sure that the file is written to the FPROM you should change it back to read only using the flash_ro script Now reset the LIAB and enter the boot loader menu by sending three dots In the parameters sub menu you should add 1iabADD additionalExample tar gzas a new parameter using the i command Finally exit the boot loader or reset the LIAB and watch for the comment printed by the rc additional script as the LIAB boots When the LIAB is fully booted you should be able to see the new homepage using your favorite web browser miniLIAB User
18. ble for firewall applications A picture of a miniLIAB microprocessor board is shown on Fig 1 Figure 1 miniLIAB microprocessor board The LIAB is distributed with a version 2 4 17 Linux kernel and a Linux file system that is an extract of the Redhat 6 2 distribution The shared libraries in Redhat 6 2 miniLIAB User s Manual 7 is based on a recent version of the GNU libc library libc6 Thus the LIAB offers a Linux environment similar to that of modern PC Linux installations applications compiled on the PC works immediately on the LIAB 8 miniLIAB User s Manual 2 The miniLIAB Board The Linux In A Box LIAB microprocessor board provides an excellent platform for small control and data acquisition systems that needs to be supervised over the Internet The LIAB utilizes the embedded Intel i886EX processor which includes all key elements of the AT version of the original IBM Personal Computer PC The on board FLASH PROM memory provide storage for the bootloader the Linux operating system and application software and data The miniLIAB is equipped with either two Ethernet connections or one Ethernet connection and three general purpose Light Emitting Diodes with drivers A block diagram of the miniLIAB board is shown in Fig 2 24 bit address bus _LLLLLLLLLY PELLLLELLLLLLLELH data bus i386EX embedded processor 386 core Interrupts Timers DMAs Serial lOs A GP IOs To suit your needs
19. blem is solved by placing these directories in four ordinary ramdiscs The initial content of the ramdiscs are stored in compressed images in Images During the boot process these images are uncompressed to the ramdiscs which subsequently are mounted The file system is illustrated in Fig 7 During normal operation disk access is limited to the directories that reside in ramdiscs as indicated by the dotted boxes in Fig 7 This ensures that the write operations are performed quickly and without wearing the FPROM However since the writes are performed to ramdiscs the changes will be lost when the LIAB is rebooted To make persistent changes to either the directories residing in the FPROM or the directories in ramdiscs or more precisly the ramdisc images in Images you have two options You can make the changes on your development platform and transfer a new disc image to the LIAB as described in section 6 2 or you can make the changes directly on the LIAB as described in section 6 3 6 2 Modifications using the Development Kit It is necessary to understand the concepts of the file system in order to make mod ification to it e g change the homepage add a user application or similarly The root file system is located in liabdisc libc of the development kit Adding new binaries and libraries should be done in this directory This file system also includes initial versions of the dev and etc directories During the boot process
20. ch code download manual decompression of gzipped images and unconditional jumps to a prescribed location of memory In addition you may enter two sub menus one for operations on the FPROM and one for editing of the boot parameters In the FLASH PROM menu you may read erase and write to the FPROM In addition you may download binary images which are programmed into the FPROM on the fly In the sub menu for the boot parameters you may view delete and enter new parameter strings which are given to the Linux kernel at boot time To ease the entering of network parameters an interactive questionnaire is implemented in this sub menu see section 4 4 4 2 No Dots Received If the five seconds elapse without the reception of three dots the boot loader will try to boot a Linux system The Linux kernel is expected to be in compressed state in the FPROM and the boot loader will thus search the FPROM for compressed images In the event that a Linux kernel image is found it will be decompressed into DRAM starting at address 0x100000 Further setup of the hardware is done initialization of interrupt controllers copy kernel parameters before a jump to address 0x100000 is performed At this stage the Linux kernel takes over The boot loader code is not used before a hard reset condition again is enforced on the 1386EX microprocessor 4 3 Boot Parameters When the Linux kernel is booted it is passed a number of configuration parameters which can
21. connect the port pin P1 1 to the RTS signal of the RS232 line driver of COM1 and PS2 can be used to set the DTR line of COMI to Vpp PS3 serves as a jumper for connecting pin 1 and 2 on J4 to either Vpp 3 3 volt or di rectly to the delivered supply power Vyy on P1 The PCB switches has the following default settings e PS1 open e PS2 open e PS3 pin 1 and 2 on J4 connected to Vpp 3 3 volt 2 4 External Connections Power and external stimulus can be applied to the Linux In A Box board through the connectors and the reset button on the right edge of the PCB see Fig 3 The five items on the right edge is listed in Table 2 JP3 COM2 etc JP2 JTAG o alsssscscs CI 5 7V P1 ower center 7 P positive ml Fe reset LEDS possible on miniLIABs P2 COM1 RS232 8 9600 baud 5 ejg Ethernet eth1 P4 Ethernet TP 10Mbit Ethernet ethO P3 Figure 3 Layout of the main components on a miniLIAB board with only one ethernet port JP4 64 pins CPU IO connector o a o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 00000000000000000000000000000000 oo oo oo oo oo oo oo oo 12 miniLIAB User s Manual mini jack Power connection The miniLIAB must be powered by a regulated DC sup ply of 5 to 7 volts center pin positive Reset button button Depressing this button resets the microprocessor and subsequently the bootloader will be entered You can e
22. control some aspects of the kernel s behavior This process is in nature identical to the passing of boot parameters from the LILO prompt to the Linux kernel on a standard PC These parameters can be modified in the Parameter Menu of the boot loader In section 3 3 it was suggested that no user intervention was taken during the first five seconds after power was applied As a consequence a Linux system was booted This time we want to get into the boot loader menus in order to look at the boot parameters Press the reset button SW1 and then immediately send three dots to the LIAB from your terminal emulator Now you will get a boot loader prompt miniLIAB User s Manual 19 THE BOOT LOADER YOU MUST SEND 3 DOTS WITHIN THE NEXT 5 SECONDS LIAB bootloader h for help Boot gt Try the h command to get a list of possible commands Boot gt h b lt size gt lt initrd gt Setup for linux to boot lt size gt is memory size in Mbyte default 16 MB lt initrd gt offset in bytes from FPROM start for experts only type q lt ret gt to boot linux d lt start gt lt end gt Display memory from lt start gt to lt end gt KE Go into the FLASH PROM utility submenu h Help this text jJ lt addr gt Jump to lt addr gt default 0x100000 1 Load images using uuencoded data p Display and edit boot and network parameters a la lilo q Quit monitor and continue boot procedure
23. cribed in section 1 This means that you are free to modify and redistribute it Also new releases will be made available for download from http www liab dk 5 1 Installation Before installing the development kit from the CD ROM you have to make sure that you have at least 300MB of free space on the hard drive of your Linux PC compatible computer To install the miniLIAB development kit you must get root access and unpack the tar file liab4C mini tgz into a suitable directory using something like tar xvz C lt MyHomeDir gt f liab4C mini tgz Most files in the development kit are owned by liab users uid 998 gid 100 The exception is the files in software liabdisc which are owned by a number of user including root root uid 1 gid 1 If convenient you might change the own ership of the files in your local copy of the development kits provided that you do not change the ownership of the files in the library software liabdisc To change the ownership of the files to e g linda users get root access and enter the development kit directory Then type find user 998 exec chown linda users 5 2 Contents of the Development Kit This description of the development kit pertain to the miniLIAB filetree as in stalled on your host PC using the installation procedure described in section 5 1 The directory hardware This directory contains hardware documentation for the miniLIAB board The doc umentation c
24. dividual pins of the pin headers miniLIAB User s Manual Inputs to LED drivers The logic state of the three pins are reflected in the illu mination of LEDs D1 D2 and D3 placed next to the Eth ernet connector This connector is only present on miniLIAB variants with LED s and only one Ethernet connector JTAG connector Used when the FLASH PROM and Xilinx CPLD is to be programmed for the first time or if the FLASH PROM has been accidentally erased Extension connector e One asynchronous serial line COM2 e One synchronous serial line Extension connector e CPU data bus 16 bits e CPU address bus 9 bits e CPU controls RD WR ADS BLE BHE RDY BS8 e Three chip select lines CS2 CS3 CS4 e Two 8 bit general purpose digital I O ports P1 and P3 These 16 port pins also have various dedicated functions e Four interrupt inputs INT5 INT6 INT7 NMI Table 1 Pin headers on the LIAB board JP1 to JP4 miniLIAB User s Manual 11 2 3 PCB Switches PS1 PS3 A number of PCB switches are placed on the miniLIAB board for configuration purposes The three PCB switches PS1 PS3 are not actual components but small areas of gold plated copper on the PCB itself The areas are placed close together and are easily shorted using balls of solder The balls can be applied using standard solder and a soldering iron and can later be removed using solder sucking braid PS1 makes it possible to
25. ds c which contains the source code for a simple application that can write a pattern to the three lower bits of the P3 I O port If the corresponding miniLIAB User s Manual 33 pins on JP4 are connected to the pins on JP1 the program is able to control the LEDs on the single ethernet LIAB s As this example is more interesting we will look at it in further detail The source code excluding the header is listed below Four important lines have been identi fied include lt stdio h gt include lt stdlib h gt Ta include lt sys io h gt 2 include lt asm i386 386EXcpu h gt int main int narg char argp int value if narg lt 2 fprintf stderr Usage Sleds lt value gt n return 1 value strtol argp 1 NULL 0 Bia if iopl 3 fprintf stderr You don t have privilege to make direct port I O n return 1 4 outb inb P3CFG amp 0x07 P3CFG outb inb P3DIR amp 0x07 P3DIR outb inb P3DIR amp 0x07 value amp 0x07 P3LCT return 0 In line 1 we include the io h header file which gives access to the iop1 function that we will need later Line 2 includes the 38 6EXcpu h header file which provides sensible names to the processor specific I O ports In line 3 it finally gets interesting Linux is a secure multi user operating system and as such it can not allow ordinary users to access the hardware directly i e not through device drivers If howe
26. e executed to set up the serial channel on COM1 and the DRAM system Last the processor is switched into protected mode To this point everything has been coded in 80386 assembler see the file software liabboot init startmeup S At the end of this file a call is made to main so the further coding can be done in the C programming language using the gcc compiler As discussed in section 3 3 the boot loader next prints a banner before it waits for five seconds looking for three dots to be received over the COM1 serial channel FPROM Menu Erasure of FPROMs Download of images to FPROMs Hardware Init Bootloader Init of serial line Main Menu and DRAM system Memory display CPU modeswitch Baudrate switching Download of images to DRAM Manual GZIP image decompression Jump to address Param Menu Display and edit of boot parameters Write to FPROM User inter vention within 5 seconds fish Ass No Compressed GZIP Scan Kernel Image FPROM scanning for compressed kernel JE and ramdiscs Linux Setup Further setup of HW to suit Linux E pump te Decompression of kernel image Figure 6 The boot loader for the LIAB board 18 miniLIAB User s Manual 4 1 Three Dots Received If in fact the boot loader receives the three dots within the five second period the boot loader enters a menu system The boot loader gives you a variety of options for display of memory baudrate swit
27. e Concept sy SA ES hoes A SAIA e 2 The miniLIAB Board 2 1 Layout ofthe miniLIAB Board 2 2 Pin Headers JP1 to JP4 0 00 0002 eee 2 3 PCB Switches PSI PS3 0 2 2 2 eee ee eee 2 4 External Connections 0 00 ee ee ra 3 Get Your LIAB Board Running 3 1 Required Items abade Gow Be ee eee Si a A Se ae 0 3 2 Unpacking and Serial Connection 000 4 4 The Boot Loader 4 1 Three Dots Received 0 0 0 eee ee ee ee 4 2 No Dots Received La 66 e sd WA Blow AO Bk RAR ded do Boot Paramelers sa SA DE fed i eM ek HSA ED ees 4 4 Network Configuration 0 0 0 000 eee eee eee 4 5 Download of Binary Images 0 000 eae 5 The LIAB Development Kit 5 1 THStAMATION SA Seia 67 ase ae eas eae A a o ae E a Steck SS 5 2 Contents of the Development Kit 6 The LIAB File System Gully The Concept as amp pq eter ac ona aes ca ae a ee Pare Do ma a 6 2 Modifications using the Development Kit 6 3 Modifications on Target 2 2 ee es 7 Developing Applications 7 1 A Simple Application 0 0 2 eee ee ees 7 2 Accessing Hardware 0 0 eee ee ee ee es 8 The LIAB Additional System or 13 13 13 15 17 18 18 18 20 22 25 25 25 27 27 27 29 31 31 32 35 4 miniLIAB User s Manual Bb The Concept ses ok o Sok Br dA GC ae AROS E E 35 BZ AM Example joss cee pa E RO a
28. e image file v located in the same directory as where cu was started you first tells the remote system in this case a LIAB that a download is to be initiated Next by issuing the command gt v the download is started A typical example is given below cu 1l dev ttySO s 9600 Connected lt communication with the LIAB board gt FPROM gt 1 gt vy deen BA DO TP BO VO A rom lt indication of download gt oes Sate Sas 862 863 lt or some other number gt file transfer complete connected lt More communication with the LIAB board gt Disconnected miniLIAB User s Manual 39 B The JTAG Interface The JTAG Joint Test Action Group is an industry standard specification devel oped for PCB testing which provides a means to test interconnects between chips on a board without using physical test probes Chips with JTAG interface includes a so called boundary scan cell for each pin on the device This cell is able to cap ture a logic level from a pin or force a logic level onto that pin Forced levels to a pin are serially shifted into the boundary scan cell via the JTAG interface and captured levels are shifted out The Intel 386EX processor includes boundary scan cells on nearly all pins which gives the ability to emulate bus cycles via the JTAG interface allowing access to peripheral devices such as FLASH PROM The JTAG interface JP2 is used when the FLASH PROM are to be programmed for the first time To
29. e source file hello c along with a number of other simple example programs are included in the directory software liabuserspace demos First we will try to compile and run the Hello LIAB application on the develop ment PC To get into this directory type cd lt PathToLIABDevelopmentKit gt software liabuserspace demos To compile the hello c file using gcc type gcc hello c o hello or alternatively use the make utility make hello It is inaccurate to say that hello c is compiled as gcc takes care of everything from preproccesing to compiling and linking The output file hello is an executable that can run directly on either the PC or the LIAB We will first try it on the PC S hello Hello LIAB As you will see the output of the program is the text string Hello LIAB Since we are satisfied with the application we will now try it on the LIAB There are a number of different protocols that can be used for copying the application to 32 miniLIAB User s Manual the LIAB using the ethernet connection though the two obvious choices are ftp File Transfer Protocol or rcp Remote CoPy For this example we will use rcp Make sure the crossed ethernet cable and the serial cable is connected between your LIAB and host PC Boot up your LIAB and connect to it from your Linux PC using e g cu as described in Appendix A To grant the user on the PC permission to rcp files to the LIAB you should login
30. ed in Appendix A Having started cu at 9600 baud and now applying power to the LIAB you will see a boot sequence like this cu 1l ttySO s 9600 Connected o miniLIAB Linux In A Box Bootloader o gt Visit http www liab dk lt Release 1 1 August 19 2002 at 15 06 by root Copyright LIAB Electronics ApS The bootloader will now search for a compressed kernel and file system and try to boot up a Linux system IF YOU WANT TO GET INTO THE BOOT LOADER YOU MUST SEND 3 DOTS WITHIN THE NEXT 5 SECONDS The asterisks at the end of the last line are time indicators each separated by a one second interval If no user intervention occurs within five seconds the boot loader will try to locate a linux system and boot it You may try this out and consequently you will see a bootup sequence like this o YOU MUST SEND 3 DOTS WITHIN THE NEXT 5 SECONDS DRAM size in Mbytes 16 Scanning FPROM memory range 0x00000000 to 0x007fffff for gzipped kernel and initrd images GZIP image no 1 found at addr 0x00010000 Filename vmlinux bin Comment lt no comment gt Timestamp Aug 29 09 46 16 2002 UTC Now Decompressing Image Nowdecompressed image 1173376 bytes CS8900A 10 MB Ethernet chip no 1 found IO base 0x0380 IRQ 8 EEPROM present and checksum of the EEPROM readout was OK CS8900A 10 MB Ethernet chip no 2 found IO base
31. he boot loader Enter the parameter submenu as described in 4 3 Now you are ready to enter your IP number subnet mask default gateway host and domainname and domain name server to the LIAB using the a command You are asked the following 1 If you want to enter the IP network specifications answer y for yes and enter the IP number and subnet mask for the primary Ethernet connection miniLIAB User s Manual 21 eth0 You are then asked if your LIAB is equipped with one or two network connections If the board has two Ethernets answer y and enter the IP number and subnet mask for the second connection eth1 Finally enter the IP number for the default gateway Review the settings and if correct type n when you are asked if you want to further change the IP settings 2 If you want to enter the host domain specifications answer y and enter the hostname the domainname and if applicable the IP number of a domain name server Review the settings and if correct type n when you are asked if you want to make further changes Please note that you need to supply a domainname in order to make the web server work properly You may use the domainname dummy in case you are on a local net without any nameserver Having entered the network parameters you may first review them using the p command and then write them back to the FPROM using the w command Param gt p 1 noinitrd no hlt root 1f00 ro liabIP 192 168 1 50
32. ile Since the file is decompressed without write enabling the FPROM it should only contain files that will be decom pressed to the ramdiscs Of course decompressing to the FPROM would also defy the purpose of being able to simply remove the package After the file has been decompressed the boot script will look for an executable file etc rc d rc additional Ifit exists it will be executed This makes the LIAB Additional System very flexible as rc additional can be a script that runs other executables It is always dangerous to modify the boot procedure as the system can become unbootable if the boot scripts contains serious errors The LIAB Additional System is however a safe way to try changes as execution of a faulty rc additonal script can be disabled by simply removing the 1iabADD line from the boot parameters This can be done even on an unbootable system 8 2 An Example The distribution includes an example of an additional package that can also be used as a framework for your own additional packages Located in the directory software liabadditional you will find a directory additionalExample that contains the files that should be included in the additional package and a script mkAdditionalExampleTarGz that can be used to build the additional package The example package only contains two files a new index html file that replaces the standard homepage on the LIAB and a rc additional script that simply prints
33. ired Items You need the following items to begin using the LIAB board e The LIAB board itself The relevant PCB switches are shorted with solder upon delivery e A serial cable In the end to be connected to the LIAB a female 9 pin DB 9 connector must be located An appropriate connector for your host computer must be located in the opposite end of the cable Wiring of a suitable cable is shown in Fig 5 e A power source A regulated DC source of 5 to 7 volts capable of delivering 3 watts is required A simple wall plugin power module with adequate power rating is usable e A host computer with a serial channel and software for terminal emulator The first login into the LIAB board can be done using the serial line Next you can use the serial line to configure network parameters such as IP number subnet mask etc e When you have configured the board with the network parameters you can take advantage of the higher communication speeds offered by the Ethernet interface If you connect directly to the host computer a crossover Ethernet cable is needed whereas any standard cable will do if you connect to an Eth ernet hub 3 2 Unpacking and Serial Connection To operate the board for the first time you need to connect it to a power source and to a host computer using the serial port connector P2 COM1 on the board Later when the network related parameters has been configured using the serial port 14 miniLIAB User s Manual
34. n ter the bootloader menu by sending three dots over the COM1 port at 9600 baud within the first five seconds after reset Alternatively the bootloader will try to boot the linux system COMI port RS232 serial line All communication with the bootloader is done trough COMI See the text on the reset switch SW1 above Linux device dev ttysSO Ethernet 10Mbit Twisted Pair TP High speed connections to local network or the Internet trough a suitable HUB Alternatively the LIAB can be connected directly to a host computer using a crossed ca ble Linux device etho 8 pins Ethernet 10Mbit Twisted Pair TP RJ45 High speed connections to local network or the Internet female trough a suitable HUB Alternatively the LIAB can be connected directly to a host computer using a crossed ca ble Linux device eth1 Table 2 Connectors on the miniLIAB board miniLIAB User s Manual 13 3 Get Your LIAB Board Running When delivered from LIAB Electronics ApS your Linux In A Box board is preloaded with a bootloader and a Linux system This system will boot when power is con nected PLEASE NOTE Electrostatic discharges ESD can da mage your LIAB board and care must be taken to avoid them You should wear a grounded antistatic wrist strap before unpacking the LIAB board from the protective an tistatic bag it was delivered in In addition the LIAB board should be kept on a grounded static free surface 3 1 Requ
35. n be used to place a copy of the original files in the mnt directory where they can then be modified mkEtcgz2 After running the mkEtcgz1 script and making changes to the configuration files in mnt this script can be used to make the changes persistent Table 3 The six scripts to help simply for the on target modification process miniLIAB User s Manual 31 7 Developing Applications In this section you will see two examples on how to use your Linux PC as a de velopment platform for dedicated code that you can upload and run on your LIAB Before you start make sure that you have entered the network parameters into your LIAB as described in section 4 4 One of the LIAB s biggest advantages as a target platform is its similarity with the development platform Because both hardware and software are very similar application that runs on the PC will almost always run on the LIAB and vice versa There are of course exceptions some PC applications require more memory than is available on the LIAB some LIAB applications use the IO ports that are un available on the PC etc Though these exceptions exists many applications can be developed and tested on the PC before being deployed on the LIAB 7 1 A Simple Application For the example we will use a variant of the classical Hello World program that we will call Hello LIAB After installing the LIAB development kit on your Linux PC as described in section 5 1 you will find that th
36. oded stream specifies the filemode and filename like this begin 644 vmlinux gz M F8 gt F 7IZP LL However no filename is needed in this context since the file is written directly to either RAM or FPROM and the string representing it is instead used to specify the load address and a POSIX 1 CRC checksum in the format lt addr gt lt crc gt begin 644 0000 1150042577 where 0000 is the load address in hex and 1150042577 is the CRC checksum in decimal During load the checksum of the binary data will be calculated and compared to the original checksum stated in the first line of the stream You can generate a file to be downloaded using a script like this named e g mkuu bin bash FILE 1 LOADADDR 2 CKSUM SLOADADDR cksum SFILE cut f1 d uuencode SCKSUM lt SFILE which is called like this Smkuu lt filename gt lt loadaddr gt gt lt uufile gt Typically you will either download a new kernel or a new disc image These are downloaded directly to the FPROM but it is also possible to download to RAM Af ter resetting the LIAB and entering three dots you are ready to download the uuencoded file If the file should be download to RAM you should stay in the main menu whereas you need to go to the Flash PROM sub menu using the f command to download to the FPROM miniLIAB User s Manual 23 Before downloading to the FPROM you need to erase all the sectors that the new file will occupy
37. ontains schematics diagrams and PCB layouts The subdirectory hardware sch Schematics diagrams for the miniLIAB microprocessor board The subdirectory hardware pcb PCB design for the miniLIAB board The directory software This directory contains software for the miniLIAB board bootloader Linux kernel and file trees for disc images to be loaded into the FLASH PROM 26 miniLIAB User s Manual The subdirectory software liabboot Source for the bootloader for the miniLIAB board This directory also contains various shellscripts relevant for download of a new bootloader a new kernel and disc images The subdirectory software liabkernel Modified kernel source of the version 2 4 17 Linux kernel which is able to boot on the miniLIAB board The directory also contains a compressed tar image of the original kernel source together with a patch file The subdirectory software liabdisc File tree for a fully operational linux system with scripts for bootup and the most relevant commands Contains network bash vi shared libs dev proc Apache httpd etc based on RedHat version 6 2 Scripts to create a disc image suitable for download to the FLASH PROM on the LIAB The subdirectory software liabuserspace Source code for the two example application that are discussed in section 7 The subdirectory software liabadditional Example package for the LIAB Additional System that can be used as framework for o
38. ootloader for revenue or if you develop a product using the bootloader for use by or on behalf of a commercial entity LIAB Electronics ApS are entitled to a royalty fee Additionally LIAB Electronics ApS should also be compensated if products us ing the bootloader is treated as proprietary thus enabling a competitive advantage to a company Please contact LIAB Electronics ApS for more details 1 1 The Concept During the conceptual phase of the development of microprocessor based control systems it is often recognized that the task of developing software takes up a ma jor part of the total time needed A mean to reduce the extent of the software task is to use an operating system OS Choosing the open sourced operating system Linux for a project will not only keep the basic cost of the software at a resonable level that is no cost at all but the software development process will also benefit from the extreme amount of applications written for Linux Due to its widespread use drivers for all sorts of hardware can be found on the Internet and the pro gramming environment is well documented both in books 4 11 3 9 but also in uncountable README FAQ Frequently Asked Questions and HOWTO files on the Internet On top of that programmers with experience in the UNIX operating system may easily migrate to the Linux since in fact Linux is yet another clone of the UNIX OS In particular classical textbooks on UNIX 2 8 1 10 a
39. pply almost directly to Linux During the hardware design phase of the miniLIAB it was decided that the hard 6 miniLIAB User s Manual ware platform preferably should be compatible with the processor in the AT version of the Personal Computer PC from IBM The main reason was that Linux runs extremely stable on this platform Luckily the processor in the PC AT the Intel 80386 has an embedded counterpart the i386EX 5 6 It contains nearly all the functions found in an PC AT timers interrupt system asynchronous serial channel and DMA channels Combining this embedded processor with nonvolatile memory e g FLASH PROM and an amount of cheap volatile memory such as DRAM a small embedded system on which the Linux OS is able to boot is ob tained Due to the compatibility of the 1386EX chip only minor changes in the source code of the Linux operating system kernel is needed to make it function To make communication between the board and the surrounding world effective and at the same time make it possible to connect the board directly to virtually all modern computers the microprocessor board is equipped with a standard high speed communication channel For this purpose 10 Mbit Ethernet is chosen By placing it all on a small printed circuit board PCB the miniLIAB is a neat single board microprocessor system for embedded applications Further by adding a sec ond Ethernet connection to the board the miniLIAB becomes feasi
40. s Manual 37 References 1 P K Andleigh UNIX System Architecture Prentice Hall Inc Englewood Cliffs NJ 1990 ISBN 0 13 949843 5 2 M J Bach The Design of the UNIX Operating System Prentice Hall Inc Englewood Cliffs NJ 1986 ISBN 0 13 201757 1 3 R Bentson Inside Linux SSC Inc Seattle WA 1998 ISBN 0 916151 89 1 4 D P Bovet and M Cesati Understanding the Linux Kernel OReilly amp Associates Inc Sebastopol CA first edition 2001 ISBN 0 596 00002 2 5 Intel Corporation Intel 386EX Embedded Microprocessor electrical specs 1996 document no 27242006 obtainable from www intel com as 27242006 pdf 6 Intel Corporation Intel 386EX Embedded Microprocessor Users s Man ual 1996 document no 27248502 obtainable from www intel com as 27248502 pdf 7 LIAB Electronics ApS Hardware Reference for the miniLIAB microprocessor board 2002 document no HR0002 8 M J Rochkind Advanced UNIX Programming Prentice Hall Inc Engle wood Cliffs NJ 1985 ISBN 0 13 011800 1 9 A Rubini Linux Device Drivers O Reilly amp Associates Inc Sebastopol CA second edition 2001 ISBN 0 596 00008 1 10 W R Stevens UNIX Network Programming Prentice Hall Inc Englewood Cliffs NJ 1990 ISBN 0 13 949876 1 11 M Welsh and L Kaufman Running Linux O Reilly amp Associates Inc Sebastopol CA second edition 1
41. stribution a 2 4 17 kernel with a MTD based file system see section 6 1 These should not be modified unless you really know what you are doing The third parameter root 1 00 specifies the device that should be mounted as the root The value 1 00 refers to the file system in the FLASH PROM The fourth parameter instructs the kernel to mount the root file system read only The last two parameters represent the network configuration These can be altered using the a command as explained in 4 4 or directly by deleting the existing lines using the d command and entering new lines using the i command After making any changes to the boot parameter be sure to save the changes to the FPROM using the w command Unsaved changes will be lost when you exit the parameter submenu 4 4 Network Configuration As described your LIAB will be equipped with a bootloader a Linux kernel image and a disc image when shipped from LIAB Electronics The kernel contains a driver for the ethernet controllers on the LIAB board and the disc image contains scripts for initializing the network system with IP number subnet mask default gateway etc At the end of the boot procedure both the network super daemon inetd and the web server daemon httpd are started Thus you may connect to your LIAB board using e g telnet and look at its web pages using a web browser The only thing you need to setup is the basic network parameters which is done using t
42. ther additional packages This is discussed in section 8 The subdirectory software minijtag The jtagMINI program that is used to load the initial software into the LIAB This is also needed if the boot loader is inadvertently deleted from the FPROM The directory pdf Documentation of the various chips used on the miniLIAB board For instance the subdirectory pdf intel contains full documentation of the 1386EX chip miniLIAB User s Manual 27 6 The LIAB File System The miniLIAB 4A distribution was the first LIAB distribution to use a Linux kernel from the 2 4 series These new kernels include a sub system for Memory Technol ogy Devices MTD such as FPROMS disk on chip devices ROMS etc The MTD sub system provides functionality to access memory devices as if they were hard drives This makes it possible to have file systems residing in the FPROM of the miniLIAB 6 1 The Concept The MTD sub system supports read write access to the FPROMS but certain char acteristics of FPROMS large sector sizes limited write cycles per sector necessi tate a special file system for proper write support Though such file systems exists JFFS JFFS2 they are still immature and we have opted for a read only root file system based on the proven ext2 The read only root file system includes all the libraries and binaries but there are certain directories that the Linux system must have write access to etc dev etc This pro
43. ver the super user wants to access the hardware he can request to be moved to a higher privilege level using the iop1 function iopl is short for I O Privilege Level In this case we ask to be moved to the highest privilege level and if this request is not granted the program exits with an error message Line 4 and the two consecutive lines configures the I O port and the lower bits of the number entered on the command line is written to the port For an explanation of the registers see 6 34 miniLIAB User s Manual To try the example first change to the right directory and then run the make tool cd lt PathToLIABDevelopmentKit gt software liabuserspace demos S make leds 8 Since the used I O ports are not present on the PC the program should only be run on the LIAB To test it follow the instructions in section 7 1 on how to transfer the program to the LIAB using rcp miniLIAB User s Manual 35 8 The LIAB Additional System During development and even in production it can be useful to be able to add and remove a software package containing several files This is the purpose of the LIAB Additional System 8 1 The Concept As part of the boot process the LIAB will look for a special boot parameter called li abADD lt filename gt If this exists the boot script will look for the file with the given name in Images and if found attempt to decompress it into the root directory The file should be a simple tar gz f
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