Universal JTAG library, server and tools ======================================== Kolja Waschk (Ed.) $Id$ ///////////////////////////////////////////////////////////////////////////// This document is formatted to be readable for "asciidoc". Before you make any changes, please read the use guide at the asciidoc home page www.methods.co.nz/asciidoc and try to adapt to the style used here; e.g. use the single-line section header style ("== header =="). Please do not use any whitespace other than SPACE (ASCII 0x20) and break lines > 79 chars. ///////////////////////////////////////////////////////////////////////////// == Copyright == Copyright 2007, 2008 Kolja Waschk and the respective authors. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation. A copy of the license is included in the section entitled "GNU Free Documentation License". //========================================================================= == General == === JTAG === // Contributed by Ralf Engels JTAG basics can be found all over the internet. This section should go into some more details about working with JTAG. What hardware do you need, what is the usage of JTAG, where do I get files. What file formats are available... ==== Introduction ==== JTAG (IEEE 1149.1) is a serial interface for testing devices with integrated circuits. The problem that the JTAG interface was designed to solve is checking if connections between ICs are OK. Therefore you can set and check in- and outputs of ICs. In order to save pins and logic a very simple serial design was invented. * One pin serial input * One pin serial output * One pin clock * One pin control The control pin (together with clock) allows to switch device states. A state machine inside each chip can be controlled, e.g. to reset the device. This control machine also allows to have two internal shift registers in each device (although we only have on in- and one output-pin). The registers are called instruction register (IR) and data register (DR). The current UrJTAG tool allows you to set the IR and set and get the DR. It doesn't allow you to directly control the statemachine (yet). ==== Interfaces ==== The simplest interface that you can build is like the Xilinx parallel cable (also called DLC5). If your device works with a 5V or 3.3V supply voltage then this device can even be build just with passive parts. (picture missing here) UrJTAG also supports a number of other interface adapters. ==== Additions ==== In the meantime the jtag specification was used as a basis for programming flash files and debugging processors. UrJTAG supports programming a couple of different flash devices. It also supports programming of non-flash devices via svf files. UrJTAG does not support debugging yet. Other open source solutions such as OpenOCD allow you to debug ARM processors with gdb. ==== BSDL and UrJTAG data files ==== The BSDL file format describes the jtag interface for one IC. It is a VHDL syntax with the needed information (like pin-names, register lengths and commands) that is usually done by the supplier. e.g. Xilinx BSDL files are all included in their free web-pack (using file extension ".bsd"). UrJTAG uses a different file format internally. So in order to add a new device to UrJTAG you need to convert those files and produce a directory structure. Currently there are at least three tools available to do that; included with UrJTAG is "bsdl2jtag". Please ask on the mailing list in case of problems with that. Please also send proven working files back to this project. Starting with post-0.7 releases, UrJTAG contains a BSDL subsystem that retrieves the descriptions for chips in the chain from BSDL files on the fly. Be aware that this feature is currently experimental and may not work with every BSDL file yet. ==== SVF files ==== The SVF file format contains a number of high level commands to drive the jtag bus. For example you can shift the IR or DR and even check for the results. The Xilinxs impact and Altera QuartusII tools allow you to write this file to program devices. The player has been developed according to the "Serial Vector Format Specification", Revision E, 8 March 1999 issued by ASSET InterTech, Inc. The full specification can be found at http://www.asset-intertech.com/support/svf.pdf UrJTAG features an "SVF player" that can read SVF files and perform the described actions on the bus. SVF parser and lexer are also copyright 2002, CDS at http://www-csd.ijs.si/. They have been reused from the "Experimental Boundary Scan" project at http://ebsp.sourceforge.net/. ==== JAM/STAPL files ==== Another format for describing actions over JTAG interfaces is STAPL, actually standardized as JEDEC "JESD-71A". Compared to SVF, it looks more like an actual programming language and features looping, conditional execution, and more. STAPL is not yet supported by UrJTAG. //------------------------------------------------------------------------ === UrJTAG === // Written by K.Waschk ==== Introduction ==== UrJTAG Tools is a software package which enables working with JTAG-aware (IEEE 1149.1) hardware devices (parts) and boards through JTAG adapter. This package has open and modular architecture with ability to write miscellaneous extensions (like board testers, flash memory programmers, and so on). JTAG Tools package is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. There is absolutely no warranty for JTAG Tools. Please read COPYING file for more info. WARNING: This software may damage your hardware! Feedback and contributions are welcome. ==== About this document ==== This documentation is far from being complete. You're encouraged to amend and supplement it and submit your changes in the Bugs or Enhancements tracker at the UrJTAG website. ==== UrJTAG Website ==== The most current version of this documentation and UrJTAG sourcecode is always available from the project homepage at http://www.urjtag.org ==== The name "UrJTAG" ==== I (Kolja) favour short names, so I thought about adding only a few letters to "JTAG". The prefix "Ur" in German means "ancestral", an "Ur-Vater" is a forefather. UrJTAG shall become the forefather, the prototype for many other JTAG tools. By mere chance the "Ur" is also another name for an aurochs, an animal similar to the GNU... ==== Authors, contributors, ... thanks ==== A list of contributors is maintained in the file THANKS in the source distribution. ==== UrJTAG and openwince JTAG Tools ==== The JTAG Tools originally were developed by Marcel Telka as part of the openwince project. Still a large portion of the source code is his work. However, the last release of the JTAG tools was version 0.5.1 in 2003. After a few years the development completely stalled. Every few months or so on the project's mailing list someone asked about continuing, but a critical mass wasn't reached before late 2007. A fork of the JTAG tools was created under the wings of the UrJTAG project at Sourceforge. //------------------------------------------------------------------------ === System requirements === //Copied from original README ==== Supported host operating systems ==== JTAG Tools should run on all Unix like operating systems including MS Windows with Cygwin installed. ==== Required software for running UrJTAG ==== Required only for MS Windows: * current Cygwin net installation from http://cygwin.com * ioperm package (a part of the standard Cygwin net installation) It may be necessary to run the command "ioperm -i" to install the IOPERM.SYS driver in the system. If UrJTAG was compiled to use the readline library, it has to be present on the system as well. It's probably a standard part of your distribution. More software is needed if you want to compile UrJTAG (which you probably want because currently no pre-compiled binaries are avaible...). See "Installation" below. ==== Supported JTAG adapters/cables ==== See 'help cable' command for up-to-date info. * Arcom JTAG Cable * Altera ByteBlaster/ByteBlaster II/ByteBlasterMV Parallel Port Download Cable * Altera USB-Blaster and compatible http://www.ixo.de/info/usb_jtag * Xilinx DLC5 JTAG Parallel Cable III * ETC EA253 JTAG Cable * ETC EI012 JTAG Cable * Ka-Ro TRITON (PXA255/250) JTAG Cable * Keith & Koep JTAG Cable * Lattice Parallel Port JTAG Cable * Mpcbdm JTAG Cable * Macraigor Wiggler JTAG Cable * Amontec JTAGkey (FT2232-based) * Olimex FT2232-based ARM-USB-JTAG * Other FT2232-based USB JTAG cables (experimental) * Xilinx Platform USB Cable (experimental) ==== JTAG-aware parts (chips) ==== The data/ directory of the UrJTAG installation has some more, but at least the following are supported: * Altera EP1C20F400 * Altera EPM7128AETC100 * Analog Devices Sharc-21065L * Atmel ATmega128 (partial support) * Broadcom BCM1250 * Broadcom BCM3310 (partial support) * Broadcom BCM5421S * Broadcom BCM4712 (partial support) * DEC SA1100 * Hitachi HD64465 * Hitachi SH7727 * Hitachi SH7729 * IBM PowerPC 440GX * Intel IXP425 * Intel SA1110 * Intel PXA250/PXA255/PXA260/PXA261/PXA262/PXA263 * Lattice LC4032V * Lattice M4A3-64/32 * Lattice M4A3-256/192 * Motorola MPC8245 * Samsung S3C4510B * Sharp LH7A400 * Toshiba TX4925/TX4926 * Xilinx XC2C256-TQ144 * Xilinx XCR3032XL-VQ44 * Xilinx XCR3128XL-CS144 * Xilinx XCR3128XL-VQ100 * Xilinx XCR3256XL-FT256 ==== Flash chips ==== NOTE: Not all chips are supported in every possible configuration, there may be untested combinations of chip type, bus width, ... * Intel 28FxxxJ3A (28F320J3A, 28F640J3A, 28F128J3A) * Intel 28FxxxK3 (28F640K3, 28F128K3, 28F256K3) * Intel 28FxxxK18 (28F640K18, 28F128K18, 28F256K18) * AMD Am29LV64xD (Am29LV640D, Am29LV641D, Am29LV642D) * AMD Am29xx040B (Am29F040B, Am29LV040B) //------------------------------------------------------------------------ === Compilation and installation === ==== Required software for compiling UrJTAG ==== To run autogen.sh, you need autoconf and automake, bison, and a recent flex. Flex 2.5.4a as it comes with Cygwin will work but some parts of UrJTAG (namely the SVF player) become more verbose if Flex 2.5.31 or newer is used. Building the BSDL subsystem files requires Flex 2.5.33 or newer. The configure script will compare the availble Flex version against these preconditions and enables or disables the related features. Furthermore, libtool should be available, and "devel" versions of the following packages: * gettext * readline (not needed, but really eases interactive use) * ioperm (needed only for Cygwin) ==== Required libraries for USB support ==== For USB adapter support (including support for parallel port adapters attached to USB-to-parallel converters), one or more additional libraries are required. Many USB JTAG adapters and USB-to-parallel converters are based on chips made by FTDI. To support these, either intra.net's "libftdi" or FTDI's "FTD2XX" library can be used. On many modern Linux distributions, libftdi is available as a precompiled package and can be installed using the distribution's package management system (e.g. "apt-get libftdi-dev" for Debian and Ubuntu). If it isn't available or you don't run Linux, you can get it from * http://www.intra2net.com/de/produkte/opensource/ftdi/ Alternatively, you can use the FTD2XX library from the chip manufacturer FTDI. It is available for Linux and Windows. To use the library for Windows in a Cygwin environment, first get it from: * http://www.ftdichip.com/Drivers/D2XX.htm Unzip the CDM*.zip to some directory and tell UrJTAG about this directory during the configure step before actual compilation: ./configure --with-libftd2xx=/cygdrive/c/windows/temp/CDM_Drivers All other USB JTAG adapters can be supported only if libusb is installed. There is a libusb-win32 variant that can be used in a Cygwin environment: * http://libusb.sourceforge.net (libusb) * http://libusb-win32.sourceforge.net (libusb for Windows) For specific notes regarding the use of these libraries in a Cygwin environmen, see below. ==== Installing from source tar.gz ==== The installation follows the standard configure, make, make install scheme: tar xzvf urjtag.tar.gz cd ../jtag ./configure make make install ==== Installing from Subversion repository ==== If you want to try the very newest version of UrJTAG... svn co http://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk urjtag cd urjtag/jtag ./autogen.sh # ./configure done by autogen.sh; run it here with special options if needed make make install ==== Linking to FTD2XX.DLL in Cygwin environment ==== Before running configure, get the D2XX drivers from FTDI. * http://www.ftdichip.com/Drivers/D2XX.htm (FTDI FTD2XX library) Unzip the archive into a directory of your choice (probably a choice without spaces in the name is better) and afterwards run configure with the "--with-ftd2xx" pointing to that directory, e.g. ./configure --with-ftd2xx="/cygdrive/e/temp/cdm" Configure should now report FTDI cable support ... via libftd2xx : yes ==== Using LibUSB-Win32 in Cygwin environment ==== Before running configure, install the LibUSB-Win32 "filter" driver from SF. * http://libusb-win32.sourceforge.net Then point configure to the directory where LibUSB-Win32 was installed (it might give problems if the path contains spaces, as "Program Files" does!): ./configure --with-libusb="/cygdrive/c/Programme/LibUSB-Win32/" ==== Building the BSDL subsystem ==== As mentioned above, building the BSDL lexer requires Flex 2.5.33 or newer. If the detected Flex version is not recent enough, configure will disable the BSDL subsystem. The detection result is summarized at the end of configure: jtag is now configured for ... Build BSDL subsystem : yes Flex is only required when you're working on a check-out of the Subversion repository. In this case Flex has to be called to transform bsdl_flex.l to bsdl_flex.c. When you're compiling from released sources, the local Flex version is not relevant since the output file of Flex is part of the tarball. I.e. even if the local Flex fails the check, the BSDL subsystem is enabled and will be compiled from the released C files. //========================================================================= == Usage == === Quick start === // Contributed by Ralf Engels ==== Run the software ==== Connect your JTAG adapter between your PC and target device and turn on your device. To run JTAG Tools type "jtag" and press Enter. jtag should start and display some initial informations. Output should end with line like this: This is "jtag command prompt". Type "help" and press Enter for initial help about available commands. To exit JTAG Tools type "quit" and press Enter. ==== Configure the cable ==== Type "help cable" for list of supported JTAG cables. Type "cable" command with arguments. Example: jtag> cable EA253 parallel 0x378 Initializing ETC EA253 JTAG Cable on parallel port at 0x378 ==== Detect parts on the JTAG chain ==== Type "detect" at the jtag command prompt: jtag> detect Your output should look like this: IR length: 5 Chain length: 1 Device Id: 01011001001001100100000000010011 Manufacturer: Intel Part: PXA250 Stepping: C0 Filename: /usr/local/share/urjtag/intel/pxa250/pxa250c0 If you get empty output or an error message your JTAG adapter is not connected properly, or your target board doesn't work, or it is turned off. The "detect" command is required before all other commands. ==== Print current JTAG chain status ==== jtag> print chain No. Manufacturer Part Stepping Instruction Register --------------------------------------------------------- 0 Intel PXA250 C0 BYPASS BR ==== Sample device pin status ==== jtag> instruction SAMPLE/PRELOAD jtag> shift ir jtag> shift dr jtag> dr 1000110010000010000110010111111111111111111001101110... jtag> print chain No. Manufacturer Part Stepping Instruction Register ------------------------------------------------------------ 0 Intel PXA250 C0 SAMPLE/PRELOAD BSR jtag> get signal BOOT_SEL[0] BOOT_SEL[0] = 0 jtag> Note: BSR is "Boundary Scan Register" ==== Burn flash connected to the part ==== jtag> flashmem 0 brux.b 0x00000000 Note: Supported configuration is 2 x 16 bit only BOOT_SEL: Asynchronous 32-bit ROM 2 x 16 bit CFI devices detected (QRY ok)! program: block 0 unlocked erasing block 0: 0 addr: 0x00002854 verify: addr: 0x00002854 Done. jtag> or: jtag> flashmem msbin xboot.bin Note: Supported configuration is 2 x 16 bit only BOOT_SEL: Asynchronous 32-bit ROM 2 x 16 bit CFI devices detected (QRY ok)! block 0 unlocked erasing block 0: 0 program: record: start = 0x00000000, len = 0x00000004, checksum = 0x000001EB record: start = 0x00000040, len = 0x00000008, checksum = 0x000001B0 record: start = 0x00001000, len = 0x00002B30, checksum = 0x00122CAB record: start = 0x00004000, len = 0x00000160, checksum = 0x0000684B record: start = 0x00005000, len = 0x00000054, checksum = 0x000008EE record: start = 0x00005054, len = 0x00000030, checksum = 0x00000DA9 record: start = 0x00000000, len = 0x00001000, checksum = 0x00000000 verify: record: start = 0x00000000, len = 0x00000004, checksum = 0x000001EB record: start = 0x00000040, len = 0x00000008, checksum = 0x000001B0 record: start = 0x00001000, len = 0x00002B30, checksum = 0x00122CAB record: start = 0x00004000, len = 0x00000160, checksum = 0x0000684B record: start = 0x00005000, len = 0x00000054, checksum = 0x000008EE record: start = 0x00005054, len = 0x00000030, checksum = 0x00000DA9 record: start = 0x00000000, len = 0x00001000, checksum = 0x00000000 Done. jtag> //------------------------------------------------------------------------ === JTAG commands === // Various authors... ==== Overview ==== Following is a list of commands currently supported by jtag and some example usage. *bit*:: define new BSR bit *bus*:: change active bus *bsdl*:: manage BSDL files *cable*:: select JTAG cable *detect*:: detect parts on the JTAG chain *detectflash*:: detect parameters of flash chips attached to a part *discovery*:: discovery of unknown parts in the JTAG chain *dr*:: display active data register for a part *endian*:: set/print endianess *eraseflash*:: erase flash memory by number of blocks *flashmem*:: burn flash memory with data from a file *frequency*:: setup JTAG frequency *get*:: get external signal value *help*:: display this help *include*:: include command sequence from external repository *initbus*:: initialize bus driver for active part *instruction*:: change active instruction for a part or declare new instruction *part*:: change active part for current JTAG chain *peek*:: read a single word *poke*:: write a single word *print*:: display JTAG chain list/status *quit*:: exit and terminate this session *readmem*:: read content of the memory and write it to file *register*:: define new data register for a part *script*:: run command sequence from external file *set*:: set external signal value *setdevice*::: force device detection *shift*:: shift data/instruction registers through JTAG chain *signal*:: define new signal for a part *svf*:: execute svf commands from file Some tools derived from the same openwince JTAG Tools code base as UrJTAG know additional commands, which are not supported in UrJTAG. See the section about "Unsupported commands", below, about workarounds. ==== Basic commands ==== ===== quit ===== This command closes the jtag console. ===== help ===== Without additional parameter it gives an overview of the available commands. With a parameter you can get more information about any of the commands. Example: jtag> help cable Most cable drivers require some more details about the cable to start properly. To learn about the details, use the "cable" command with the name of the cable followed by the word "help". Example: jtag> cable wiggler help ===== include ===== Run commands from a named script file installed with UrJTAG. The directory prefix is added automatically (e.g. /usr/share/urjtag/, depending on your installation). For example, the following startup sequence configures the cable, chain, and loads definitions and bus driver for a Samsung S3C4510B CPU to peek its memory at 0x0: jtag> cable wiggler ppdev /dev/parport0 jtag> detect jtag> include samsung/s3c4510b/s3c4510b jtag> peek 0x0000 ===== script ===== Run commands from a named script file located anywhere. No directory prefix is added. A number X may be specified after the name of the script file, causing the script to be run X times. ==== Part definition commands ==== The following commands are also used in the data files to define a device (IC) on the jtag bus. It is not recommended to use these commands in an interactive session. Instead you should produce a device definition file out of a .bsd file using one of the supplied tools. * bit * register * signal ==== Flash commands ==== These commands can be used if the device supports flashing. * detectflash * flashmem * eraseflash ==== Chain management ==== ===== cable ===== Sets and initialized the cable driver. This is usually the first command that you are executing in a session. Example: jtag> cable EA253 parallel 0x378 Initializing ETC EA253 JTAG Cable on parallel port at 0x378 For a parallel cable using the ppdev driver you would use this: jtag> cable DLC5 ppdev /dev/parport0 If you get an error, it may be that the parallel port kernel driver was compiled as a module in your Linux kernel and wasn't loaded automatically. Then you should try to load the ppdev driver manually (with root rights outside the jtag shell): modprobe ppdev modprobe parport modprobe parport_pc ===== detect ===== Detects devices on the bus. Example: jtag> detect IR length: 5 Chain length: 1 Device Id: 01011001001001100100000000010011 Manufacturer: Intel Part: PXA250 Stepping: C0 Filename: /usr/local/share/jtag/intel/pxa250/pxa250c0 During "detect", UrJTAG searches through the files in its database (usually in /usr/share/urjtag) to find a match for the manufacturer, revision and part number for the IDCODE read from the part. However, not all parts identify themselves in a way that is useful for "detect". For example, many chips with an ARM processor core inside present an IDCODE that may be specific to the the particular core inside the chip (e.g. ARM7TDMI), but doesn't tell about the actual manufacturer of the chip. In such case, the data for the part has to be included manually. See also the documentation for the "include" command. ==== Highlevel commands ==== ===== svf ===== The SVF player operates on a single part in the scan chain. Therefore, you have to bring up the jtag software, specify a cable and detect the scan chain beforehand. The player will establish a new instruction called "SIR" and a new register called "SDR". They are used internally by the respective SVF commands and are reassigned with new values as the player advances through the file. It is not recommended to use them outside of the SVF player as their content is dynamic. An example session: jtag> cable ppdev /dev/parport0 DLC5 Initializing Xilinx DLC5 JTAG Parallel Cable III on ppdev port /dev/parport0 jtag> detect IR length: 5 Chain length: 1 Device Id: 10010000101000100000000010010011 Manufacturer: Xilinx Part: XC2S300E-PQ208 Stepping: 9 Filename: /usr/local/share/jtag/xilinx/xc2s300e-pq208/xc2s300e-pq208 jtag> part jtag> svf jtag> instruction BYPASS jtag> shift ir jtag> part jtag> svf jtag> instruction BYPASS jtag> shift ir It is recommended to set the part's instruction register to BYPASS although most SVF files do this at the end. By setting the instruction explicitely to BYPASS the output of the print command will always show meaningful information. The SVF player will issue messages when situations arise that cannot be handled. These messages are classified as warnings or errors depending on whether the player can continue operation (warning) or not (error). In case the TDO parameter of an SDR command leads to a mismatch the player issues a warning and continues. If the player should abort in this case then specify 'stop' at the svf command. .Limitations and Deficiencies ***************************** Several limitations exist for the SVF player. It has been tested so far with files generated by these tools: - Xilinx ISE WebPack 6.3.02i - 9.1.02i - Altera Quartus II 4.1sp1 - 7.0 Configuration for these devices has been tested so far: - Altera EPC1C12Q240 - Altera MAX3032, EPM3032ALC44 - Altera MAX3064, EPM3064ALC44 - Altera MAX7032, EPM7032SLC44 - Altera MAX7064, EPM7064SLC44, EPM7064STC44 - Xilinx Spartan-IIE, XC2S300E-PQ208 - Xilinx Spartan-3, XC3S1000-FG456, XC3S5000-FG900 The implementation of some SVF commands has deficiencies. - HIR, HDR commands not supported. + Their functionality should be covered by the part concept of JTAG Tools. - PIO command not supported. - PIOMAP command not supported. - RUNTEST SCK not supported. + The maximum time constraint is not guaranteed. - SIR + No check is done against the TDO parameter. - TRST + Parameters Z and ABSENT are not supported. - TIR, TDR commands not supported. + Their functionality should be covered by the part concept of JTAG Tools. Operation can be slowed down significantly when the FREQUENCY command has been specified. This is not a problem of the SVF player itself but seem to happen when the frequency of UrJTAG is set to a value larger than 0. Configuration takes very long although the maximum allowed frequency is 10 MHz. Consider to comment out the FREQUENCY command at the beginning of the SVF file. ***************************** ===== bsdl ===== The 'bsdl' command is used to set up and test the underlying BSDL subsystem of UrJTAG. Whenever 'detect' encounters a new part, a configuration process is started. This involves matching the retrieved IDCODE against the part descriptions in /usr/share/urjtag as described above. However, before this database is searched for a suitable description, the BSDL subsystem is started and searches for BSDL file that matches this device. If it finds a matching file, traversal of the /usr/share/urjtag database is skipped. If not, then this standard process follows. To tell the BSDL subsytem where to look for BSDL files, the 'bsdl path pathlist' command has to be issued prior to 'detect'. The contents of 'pathlist' must be a semicolon-separated list of directories where BSDL files are located. This list is stored by 'bsdl path' and is used lateron when 'detect' calls the BSDL subsystem. IMPORTANT: The BSDL subsystem applies the first BSDL file that parses without errors and that contains the correct IDCODE. Scanning the specified directories happens in extactly the given order. Inside a directory however, the order depends largely on your filesystem's behavior. Further details of the 'bsdl' command: - bsdl path [;[;]] + set paths for locating BSDL files - bsdl debug on|off + switches debug messages on or off - bsdl test [file] + reads file (if specified) or all files found via 'bsdl path' and prints a short status, an active part is not required - bsdl dump [file] + reads file (if specified) or all files found via 'bsdl path' and prints all configuration commands, an active part is not required TIP: The 'bsdl dump file' command implements the same functionality as bsdl2jtag. ==== Unsupported commands ==== ===== setdevice ===== This command was only there to support the SHARC 21065L processor, which has no IDCODE and therefore can't be initialized correctly by just running "detect". However, the proper initialization can be done after "detect" by loading the proper declarations and bus driver manually: jtag> include analog/sharc21065l/sharc21065l //======================================================================== == Internals == This section yet is only a placeholder for the information that will be added soon... === Files === ==== Source code Overview ==== doc/:: Documentation data/:: Part descriptions (Data files) include/:: C header files src/:: C source code src/bsdl:: BSDL subsystem src/bus:: Bus driver for various CPUs and other parts src/cmd:: Implementation of the commands for the "jtag" shell src/flash:: Flash detection and programming algorithms src/jim:: JIM, the JTAG target simulator src/lib:: Utility functions src/part:: Functions for accessing specific parts in a chain src/svf:: SVF player src/tap:: Functions for accessing the chain in general //------------------------------------------------------------------------ === Drivers === * Cable-specific drivers * Parport drivers * TAP drivers * Chain drivers * Bus drivers * Flash drivers * Commands ==== Cable-specific drivers (src/tap/cable) ==== Cable-specific drivers are those which are visible to the user through the "jtag" command shell. They're listed in response to the "help cable" command. Each driver has to provide the following functions: * connect(), init() - Initialization * done(), cable_free(), disconnect() - Cleaning up * clock(), get_tdo(), transfer() - immediate JTAG activities * flush() - internally used to actually perform JTAG activities * help() - a help text to be displayed by the jtag command shell ===== Initialization ===== After allocating a "cable_t" structure, a pointer to it and further parameters (as strings) have to be passed first to the selected cable's connect() function. Following that, the init() function is called via cable_init(). If cable_init() returns a zero value, all is fine and the cable is ready for use. ===== Cleaning up ===== There are two functions for actual cleanup: * done() is responsible for driving the hardware to a safe and consistent state. * cable_free() then can be used to clean up eventually extra allocated memory etc. Both are usually called from chain_disconnect(). An additional mechanism allows to clean up if a disconnection was detected by the low level driver (e.g. USB or parallel port driver). A cable has to provide a disconnect() function for this purpose: 1. Low level (e.g. parport) driver calls cable driver->disconnect() 2. cable driver->disconnect() calls chain_disconnect() 3. chain_disconnect() calls cable driver->done() 4. chain_disconnect() then calls cable driver->cable_free() After return from chain_disconnect() to cable driver->disconnect(), the cable_t structure has been freed and must not be accessed anymore. ===== JTAG Activities ===== Currently the API provides five different functions for performing operations at the JTAG interface on the low level signal level (using the four signals TMS, TCK, TDI, and TDO). * clock(tms,tdi,n) takes values for TMS and TDI output as its parameters, ensures that actual cable signals are set accordingly, and does a 0-1 transition on TCK (n times) * get_tdo() returns the current value at the TDO input. * set_trst(x) sets the TRST signal and returns the current value. * get_trst() returns the current value of the TRST signal. For many JTAG adapters, there's almost no delay when doing alternating clock() and get_tdo(). Writing and reading happens immediately and the result is available immediately as well. This is the case with most parallel port adapters (but not when attached to USB-to-parallel adapters or USB docking stations) and memory mapped IO (e.g. general purpose I/O pins of microcontrollers). But there are adapters, especially USB and Ethernet based adapters, which exhibit a rather long delay between the initiation of reading a bit and the delivery of the value of the bit. It is at least 1 millisecond with USB, which would limit the transfer rate to 1 kHz. One way to workaround this is to transmit bits compacted into bytes and chunks of bytes, which is possible with the transfer() function. * transfer(in, out) The transfer() function does a series of TCK pulses, with data for TDI read as bytes from memory. The bytes are automatically serialized. TMS is set to zero during transfer()s. Optionally, prior to each bit shifted out to the interface, TDO input can be read into memory (deserialized into a byte array of the same size as the input array). It still doesn't yield much improvement if the operation consists of many read and write transitions (e.g. repeatedly writing an instruction and some data register values, then reading from the data register, as it is necessary for memory access). For that reason, the above functions are also available in variants that don't cause immediate activity, but rather schedule it for later. In the API, they're visible as * cable_defer_clock() * cable_defer_get_tdo() * cable_defer_set_trst() * cable_defer_get_trst() * cable_defer_transfer() These functions aren't implemented in the cable driver (but currently in src/tap/cable.c). The cable driver just has to provide a flush() function to actually execute the queued activity in some cable-specific optimal way, and to store the results of get_tdo() and transfer() activity. The caller later can pick up the results using these functions (implemented in cable.c): * cable_get_tdo_late() * cable_get_trst_late() * cable_transfer_late() As an example, consider the following sequence of activities: 1. clock() 2. get_tdo() 3. clock() 4. get_tdo() If the result of the first get_tdo() isn't absolutely required before the second clock(), the sequence can be optimized into the following sequence (if 1. defer_clock() 2. defer_clock() 3. flush() 4. get_tdo_late() 5. get_tdo_late() The next sections explain the queueing mechanism and its limits in detail. ===== When flushing occurs ====== The cable_flush() function is used to flush the queue towards the cable. It takes one additional argument, "how_much", which may be one of * OPTIONALLY: The cable driver may flush if it's reasonable (e.g. if the queue has been filled so that some buffer limit for the cable interface is reached). It would be wise to flush early to keep the queue small, if there is no point in queueing up more items because the transfer to the cable would have to be split into smaller chunks anyway. This is used by UrJTAG immediately after adding items to the queue. * TO_OUTPUT: The cable driver should at least flush as much so that one output becomes available in the output queue. If there's already something in the output queue, this should be interpreted similar to OPTIONALLY. This is used by UrJTAG immediately before it wants to use that output. * COMPLETELY: The cable driver has to flush the queue completely. This is used by UrJTAG immediately before actions that circumvent the queueing such as calls to the legacy clock/get_tdo functions. It could also be used by application code to ensure that some action is actually done in time. ===== JTAG activity queueing ===== The source in src/tap/cable.c provides to important functions to access the two queues "todo" (with activity to be done) and "done" (with results): * cable_add_queue_item * cable_get_queue_item In src/tap/cable/generic.c you'll find two implementations of dequeueing algorithms, i.e. implementations of the flush() function. These could be used by any new cable driver unless it provides a more sophisticated algorithm itself: * generic_flush_one_by_one() simply calls the "classic" functions one after another. The performance of the cable driver using this implementation will be the same whether the immediate or defer variants of the functions are used. * generic_flush_using_transfer() tries to optimize as many clock() and get_tdo() by transforming them into calls to transfer() instead. This can give a slight advantage. The generic implementations also serve as a template for new cable-specific implementations. ===== Generic implementations ===== As a reference and in many cases completely sufficient for new cables, take a look at the code in src/tap/cable/generic.c, which contains generic routines, suitable for parallel port based cables (and some for other types of cables as well). === Data file format === // By Marcel Telka JTAG declarations files are located in directory "data". The files contains common part specific JTAG information in parseable form, e.g. list of the JTAG commands, boundary scan register, list of JTAG registers, etc. Syntax of the JTAG declaration file is defined in the following subsections. ==== General rules ==== JTAG declaration file is text file which consists of lines. Empty lines are ignored. Text after first "#" on the line to the end of line is ignored. This is useful for comments. All other lines are significant. Each significant line consists of tokens separated by whitespace. Whitespace could be spaces and/or tabs. ==== Signal Definition ==== Signal definition line consists of word "signal" followed by whitespace and signal name (without spaces in the name). Rest of the line should contain whitespace separated list of pins of the part. This list is currently not used for any purpose in JTAG Tools. It is intended for future use. //------------------------------------------------------------------------ === Development === ==== Future Plans ==== - C API and library package - Bindings for Python, Perl, ... - TCP/IP access - New cable drivers - ... ==== How to contribute ==== * Using Subversion * Create and submit a patch * Use SourceForge trackers //======================================================================== == F.A.Q. == For a list of known problems in current versions, please also check the "Bugs" tracker at the UrJTAG website! Q. When I type "cable parallel 0x378 DLC5" (in a Cygwin environment) I get "Unknown port driver: parallel"?:: A. Please install the Cygwin ioperm package, and re-configure/compile. Q. When I type "cable parallel 0x378 DLC5" (in a Cygwin environment) I get "Error: Cable initialization failed!".:: A. Please install ioperm.sys driver using `ioperm -i` command. Q. When running autogen.sh, I get "Can't exec "autopoint": No such file or directory":: A. You need the headers for gettext (e.g. Debian package "gettext-devel"). Q. During compilation, I get "svf_bison.y: No such file or directory":: A. You need "bison". Q. During compilation, I get "flex: can't open ... src/svf/svf_flex.l":: A. You need "flex" Q. During compilation, I get "src/svf/svf_flex.l", line 27: unrecognized %option: bison-locations":: A. You need a newer version of flex. It should be 2.5.31 or newer; Unfortunately, Cygwin comes with only 2.5.4a. You may try to compile and install a newer version of flex from source to solve this. //======================================================================== == Licensing == === Overview === Three licenses are used for the UrJTAG project. The GPL is used for most of the code except for the files in the inclow/ subdirectory; the FDL is used for this documentation. The files in the inclow/ subdirectory are subject to different licensing as described in the file inclow/COPYING. === GNU Free Documentation License (FDL) === ......................................... include::fdl.txt[] ......................................... === GNU General Public License (GPL) === ......................................... include::gpl.txt[] .........................................