In this demonstration, i soldered 12 pin header on my router wrt54gs. This blog post will describe how to setup your environment and use the jlink to debug during both uboot and kernel development. Universal jtag library, server and tools discussion. Fourpin plus powerground interface designed to test connections between chips. Most arm processors found in embedded application have a jtag interface, for debugging hardware and software while the system is running. This software was found on the downloaduk website, along with other helpful jtag tools. This program is for debricking the wrt54ggs routers. Software run on a bare metal system that allows for selfhosted debug. Debugging a system without making any assumptions about the software running on that system. System software debug with jtagxdp and event trace. System software debug with jtagxdp and event trace by robertmuelleralbrecht, published on february 3, 20 this translates directly to a more complex software stack, that has its own challenges for guaranteeing consistent reliability throughout the devices life cycle. Generally yes you can jtag as a debugger has absolutely nothing to do with what software you happen to be running on that processor. If your router like the linksys wrt54g series already has the standard 12 pin jtag pads on the pcb, you mostly like do not need to solder wires on your pcb. Now the wire is ready now the circuit board has to be prepped as well.
Jtagxdp debugging for firmware, os level system and device driver debug, using a jtag interface is the most commonly used method in the embedded intelligent systems world. Use the mixedsignal features to measure power supplies, clock frequencies or test dacs and adcs. Jtag flash programmer software free download jtag flash. And jtag was explicitly designed to have manufacturer extensions in for debuglike purposes, so its not comparable to spi etc. If someone is willing to instruct me on how to build a config file for this chip by issuing urjtag commands and scanning the chips pins, im willing to try it and post the results for the benefit of the community. He specifically talks about using an unbuffered cable and pointedly notes that the cable he uses does not tie pin 1 of the jtag header to anything. Reenabling jtag and debugging the wrt120n devttys0.
It specifies the use of a dedicated debug port implementing a serial communications. The jtag software is still in active development by tornado on ddwrt forums as tjtag. This article covers the use of the intelr system debugger for system software stack debug on android based ia32 and intelr 64 devices. Debugging using segger jlink jtag boundary devices. Jtag vpi client driver for openrisc reference platform soc. Physical connection to tap controller is made in software bitbanging mode. This means that whenever the jtag adapter was connected to the jtag header, the system thought that the reset button had been pressed. I didnt find an official homepage, so i got the sourcecode from the ddwrt people. Conversely, i never use jtag for board level testing, only for doing debug. It provides a graphical view of jtag chains, giving you complete control, on a pinbypin basis, of both pin state either driven as an output or tristated as an input and pin value either high or low when driven.
As of 12 september 2006 the most recent version is v4. All you need is a short adapter cable, a piece of software, and of course a jtag header on your devices circuit board. Configuration is performed by manipulating a state machine one bit at a time via tms pin, then transferring one bit of data in and out per tck clock via. Actually i tried several address big boundaries, including 0x1fc00000 but none replies. Connect the cable to the pc then the wrt150n jp1 and power up the wrt150n. Create a project open source software business software top downloaded projects. In most cases it is a 12 to 14 pin header which must be assembled with 2,54mm pins. However, this means that jtag is likely being disabled in software. Gdb remote stub backend for debugging an embedded arm system via jtag common hardware debug interface. Diygadget provides solderless solution for these routers. Arm debug interface architecture specification adiv5. Its free software and the credit goes to hairydairymaid a. Otherwise you many need to solder idc headers on your boards jtag pads or holes. Since i dont have enough experience with jtag, mips and urjtag to debug the issue myself, i looked for another solution.
This is a mirror of the original hairydairymaid jtag debrick utility v4. He said that he flashed the killer and reseted the modem, but after this, the 4 ethernet leds and the internet led still on and the other leds ar. As the links above demonstrate, there are many hardwaresoftware pairs thatll get you up and debugging. The jtag header is usually located near the flash chip. Essentially, you can use jtag hardware to send particular commands to the debug unit of your microcontroller, but the actual debug commands are cpuchipetc specific. Unbrick wrt54g v8 with jtag a friend of mine bricked his brand new linksys wrt54g v8 while trying to install dd wrt. Jtag is a useful tool that allows customers additional debugging options. Virtually everyone who uses this software opts for an unbuffered cable, and the software itself, by default, expects this type of. Additionally, when depressed, the reset button asserts this pin low. Communication is done via standard tcpip gdb remote serial protocol. I think reading too much into the acronym is a mistake as with many acronyms.
I have a nonsilabs jtag adapter based on an ftdi chip, which will scan the jtag interface and does find the f122 i cant however, seem to get the silabs usb debug adapter to talk to the f122 jtag is selected in the software. Ddwrt forum view topic unbrick wrt54g v8 with jtag. Jtag is essentially a hardwarelevel communications interface. Blog how i bricked and debricked my linksys wrt54gl router.
Jtag named after the joint test action group which codified it is an industry standard for verifying designs and testing printed circuit boards after manufacture jtag implements standards for onchip instrumentation in electronic design automation eda as a complementary tool to digital simulation. This preface introduces the arm debug interface architecture specification adiv5. I wrote a couple of posts about it, and today i managed to connect it to a real target. Exactly for this purpose, in 1985 the jtag joint test action group interface was created, a standard ieee 1149. Then some debug and test interfaces integrated into the chips processor, microcontroller, soc, fpga, etc. Where you can get into trouble is the cache, for example if you stop the processor want to change some instructions in ram, and restart, the changing of instructions in ram is a data access, which does not go through the instruction cache but the data cache, if. The jt 5705 series offer a unique combination of jtag tap controller tester interfaces plus digital and analog io in compact desktop package. The most famous software for jtag is probably the linksys debrick utility by hairydairymaid aka lightbulb. Ddwrt forum view topic wrt54gtm nonjtag cfeupdater. Ujmodem is a software based on usb jtag nt and provide better ui as well as continue support cli.
Joint test action group, referring to ieee standard 1149. I am able to connect to the gdb server that openocd listens on, but looking at the registers, and instruction pointers etc. Jtag software is available from tornado a ddwrt developer. Segger was kind enough to send us a jlink plus probe for us to test. All the code that i used here is present on my jtagduino github repository i have an olimex stm32p152 board, and i wanted to connect to its jtag interface with my arduino uno. This allows easy adaptions to support multiple bus interfaces.
Add your own capability through use of corecommander fpga our generic bridgetranslator system. Qbprogrammer qbp is a software tool that is used to erase, write, and verify programs on the target system or fa adapter, on which an nec electronics singlepowersupply on chip flash memory microcontroller is mounted, by using the onchip debug. Two corner cases of jtag software debug implementation first case. Usbjtag nt provide faster programming speed and wider range of target support. This is a fork of the work the ethzurich did on the advanced debug interface from opencores. By adding xjanalyser functionality to standalone xjdeveloper, the xjtag development system is an integrated development environment ide for the development and debugging of jtagbased test and programming systems the xjtag professional development system is supplied with an additional xjio test extension board that allows you to improve test. But linksys routers should all have the same layout, right. Free jtag software from intellitech enables you to use the power of internal jtag silicon instruments with a commercial quality tool.
These engineers have no control over th e design decisions that are made in the adiv5 interface implementation to which they connect, but must be able to. Inside the zip file download for the hairydairymaid wrt54g debrick utility v48 there is a pdf file that describes the software and how to use it. Urjtag is free software, covered by the gnu general public license, and you are welcome to change it andor distribute copies of it under certain conditions. Solve problem with debugging linksyswrt54gl with jtag. Some tutorials mostly those written for wrt54g routers used a 10 pin connector for the jtag cable, others used the 12pin one. The original openwrt hairydairymaid jtag software wrt54g does work with ti ar7 via custom configuration options using the very poormans xilinx buffered parallel port cable.