- JTAG Connectors, Joint Test Action Group
- JTAG pinouts
- JTAG - Joint Test Action Group
- JTAG Pinouts
- 6 pin RJ12 (6P6C) female connector
JTAG Connectors, Joint Test Action GroupIn addition, one of the pins freed up by this can be used for Single Wire Viewing SWVwhich is a low cost tracing technology which is used by the "Red Trace" functionality within Red Suite. Resistors should be added externally onto the board as detailed above. You may use resistors between 10K and K for these signals. This will prevent the signals from floating when they are not connected to anything. For example on LPC17xx this is P2. Always ensure that you have a 10K to K Ohm pull up resistor on the ISP pin, otherwise you are unlikely to be able to make a successful debug connection. You may want to add jumpers to your hardware to accomplish this. Cortex pin 0. Some boards use un-shrouded pin headers. Always ensure that you connect your cable correctly, typically by matching the "1" marked on the board to the red -stripe on the cable. Such a cable is supplied with the RDB If you do this, then it is recommended that you remove the original way cable, and certainly do not connect both cables to boards at the same time! Where both are supported, there are special sequences defined to switch from JTAG mode default to SWD mode and vice versa that can sent to the core. However this can be modified by editing the launch configuration for a project. The voltage at Vtref is coming from your hardware, thus you need a good GND, shared with your target hardware. The usual cause of this is that your target has it's own PSU and has a ground differential slightly different from your debug PC. Power If you have designed your debug circuit according to the specification, you should also check that sufficient power is being supplied to your target. Search Search:. This Page show changes get info show raw text show print view delete cache attach file check spelling show like pages show local site map. User Login.
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 on-chip instrumentation in electronic design automation EDA as a complementary tool to digital simulation. The interface connects to an on-chip Test Access Port TAP that implements a stateful protocol to access a set of test registers that present chip logic levels and device capabilities of various parts. The Joint Test Action Group formed in to develop a method of verifying designs and testing printed circuit boards after manufacture. The JTAG standards have been extended by many semiconductor chip manufacturers with specialized variants to provide vendor-specific features. In the s, multi-layer circuit boards and integrated circuits ICs using ball grid array and similar mounting technologies were becoming standard, and connections were being made between ICs that were not available to probes. The majority of manufacturing and field faults in circuit boards were due to poor solder joints on the boards, imperfections among board connections, or the bonds and bond wires from IC pads to pin lead frames. In the same year, Intel released their first processor with JTAG the which led to quicker industry adoption by all manufacturers. Ina supplement that contains a description of the boundary scan description language BSDL was added. Although JTAG's early applications targeted board level testing, here the JTAG standard was designed to assist with device, board, and system testing, diagnosisand fault isolation. Today JTAG is used as the primary means of accessing sub-blocks of integrated circuitsmaking it an essential mechanism for debugging embedded systems which might not have any other debug-capable communications channel. Those modules let software developers debug the software of an embedded system directly at the machine instruction level when needed, or more typically in terms of high level language source code. System software debug support is for many software developers the main reason to be interested in JTAG. Frequently individual silicon vendors however only implement parts of these extensions. There are many other such silicon vendor-specific extensions that may not be documented except under NDA. Processors can normally be halted, single stepped, or let run freely. Data breakpoints are often available, as is bulk data download to RAM. Most designs have "halt mode debugging", but some allow debuggers to access registers and data buses without needing to halt the core being debugged. Some toolchains can use ARM Embedded Trace Macrocell ETM modules, or equivalent implementations in other architectures to trigger debugger or tracing activity on complex hardware events, like a logic analyzer programmed to ignore the first seven accesses to a register from one particular subroutine. For example, custom JTAG instructions can be provided to allow reading registers built from arbitrary sets of signals inside the FPGA, providing visibility for behaviors which are invisible to boundary scan operations. Similarly, writing such registers could provide controllability which is not otherwise available. JTAG allows device programmer hardware to transfer data into internal non-volatile device memory e.
JTAG - Joint Test Action Group
Recover from a Bad Flash. I think it is very important to introduce some router basics before we get started. Because we are going to work on these stuff later on to save your router. It can hold its contents when the main power source is lost. Most bricked routers are caused by a wrong configuration file. The kernel is the central component of router. Its responsibilities include managing the router's resources the communication between hardware and software components. CFE is used to bootstrap the OS. If you have read this far, it means the only way to debrick your router is by using a JTAG cable. Sorry to hear that! However, don't worry, the steps are really straightforward! Unscrew the antennas from the back you may need to slide back the antenna caps to unscrew the antennas :. There is no screws to hold the faceplate. Turn the unit upside down and place your hands between the feet on the side, then push on the blue feet with your thumbs, the faceplate and the back cover are off now:. The initial version of the utility is the very famous HairyDairyMaid Debrick utility. You can get it from here:. This is the exciting part of this tutorial. This is what you will receive in your purchase. The solderless pins are provided for solderless operation:. All you need to do is solder the 12 pin headers on the JTAG port of the router, and then connect the JTAG Cable's black header on the 12 pin header you just soldered on the pcb. Make sure pin 1 of the cable is connected to pin 1 on the board. The pin 1 of the cable can be identified by a little triangle on the black header. Pin 1 on the pcb is marked. We only need 6 solderless pins for the connections because JTAG only uses 6 pins. From the schematic above, we know only the following pins on the 12 pin headers are used: 3, 5, 7, 9 and GND. The wire 6 is the only GND wire of the header so make sure you insert a solderless pin in hole 6 not 2, 4, 8, 10 or 12 :. Now, let's see how we make the connection. Put the spring loaded solderless pins on top of the JTAG pads, align the pins with the pads, make sure all 6 pins are connected to the corresponding pads. Give it a little pressure, you will feel the little resistance. The pins are spring loaded with crown headers, so if you give it a little pressure and it will 'clamp' to the pads and won't move at all. Try it! Before we try to 'permanently' attach the pins to the pads, let's make sure other connections are finished. However, it is very likely you will need to solder the wire on the board. You can check the schematic above for details. Make sure use wire 6 of the 12 pin flat cable for ground. Jump to: navigationsearch. Personal tools Log in.
All pins marked NC are not connected inside J-Link. Any signal can be applied here; J-Link will simply ignore such a signal. They should also be connected to GND in the target system. Pin 2 is not connected inside J-Link. A lot of targets have pin 1 and pin 2 connected. Some targets use pin 2 instead of pin 1 to supply VCC. J-Link will also work if this pin is not connected, but you may experience some limitations when debugging. Pin 19 5V-Target supply of the connector can be used to supply power to the target hardware. Supply voltage is 5V, max. The output current is monitored and protected against overload and short-circuit. It is currently tested with Cortex-M3 only. The SWO can output trace data in two output formats, but only one output mechanism may be selected at the same time. Serial Wire Viewer uses the SWO pin to transmit different packets for different types of information. The three sources in the Cortex-M3 core which can output information via this pin are:. Skip navigation. It is used to check if the target has power, to create the logic-level reference for the input comparators and to control the output logic levels to the target. It is normally fed from Vdd of the target board and must not have a series resistor. It is reserved for compatibility with other equipment. Connect to Vdd or leave open in target system. This pin is normally pulled HIGH on the target to avoid unintentional resets when there is no connection. It is recommended that this pin is pulled to a defined state on the target board.