Talk about Jtag, Jlink and Ulink

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Talk about Jtag, Jlink and Ulink [Copy link]

JTAG is a parallel port of a computer. JTAG is also an international standard test protocol (IEEE 1149.1 compatible), mainly used for internal chip testing. Most advanced devices now support the JTAG protocol, such as DSP, FPGA devices, etc. The standard JTAG interface is 4 lines: TMS, TCK, TDI, TDO, which are mode selection, clock, data input and data output lines respectively. The definition of the relevant JTAG pins is: TCK is the test clock input; TDI is the test data input, and the data is input into the JTAG interface through the TDI pin; TDO is the test data output, and the data is output from the JTAG interface through the TDO pin; TMS is the test mode selection, and TMS is used to set the JTAG interface to a certain test mode; TRST is the test reset, input pin, and low level is valid. JLINK uses USB, J-LINK emulator V8 version, and its emulation speed and function are far from comparable to the simple parallel port WIGGLER debugger. J-LINK supports ARM7, ARM9, ARM11, Cortex-M3 cores, and supports ADS, IAR, and KEIL development environments. In addition to all the functions of the previous version V7.0, the V8.0 version has improvements in both software and hardware: (1) The SWD hardware interface of the V8.0 version supports 1.2-5.0V target boards, while V7.0 can only support 3.3V target boards. (2) V8.0 uses a dual-color LED to indicate more working states, while V7.0 only has one LED indicator. (3) V8.0 enhances the JTAG drive capability and improves the compatibility of the target board. (4) The firmware structure is optimized to expand the application area. J-Link ARM main features: ULINK-ULINK2 is the latest emulator launched by ARM to support RealView MDK, and is an upgraded version of the ULink emulator. ULINK2 not only has all the functions of ULINK emulator, but also adds serial debugging (SWD) support, return clock support and real-time proxy. By combining RealView MDK debugger and ULINK2, development engineers can easily perform on-chip debugging (using on-chip JTAG, SWD and OCDS) and Flash programming on the target hardware. JLINK is more powerful than JTAG, because JTAG uses a parallel port, so it is not convenient to use, and its functions are not as good as JLINK. I have not used ULINK, but it seems to be more powerful.