JTAG build the Wiggle Cable. the the "Wiggler Buffered JTAG Programmer" is compatible with the old OCD. This schematic has been tested and it is working. OCD, Experimental hack. Experimental hack to set a hardware breakpoint inside OCD Commander [media:hardbreak.tgz]

Xilinx In-System Programming Using an Embedded The TCK and TMS signals should be buffered and routed to minimize skew between TMS and TCK. 5. The integrity of the JTAG TCK signal is critical. Figure 1: Microcontroller and JTAG Chain Schematic TMS TCK TDO TDI VREF N/C N/C 14 1 VCC FPGA TCK TDI TMS TDO PROM TMS TDO CPLD TCK TDI TMS TDO Device TCK TDI TDO Processor 10 k GND GND GND GND GND Config TIAO Universal JTAG Cable As A Buffered Xilinx The key points of the schematic are as follows: PIN 2 of DB25 is TDI; PIN 3 of DB25 is TCK; PIN 4 of DB25 is TMS; PIN 13 of DB25 is TDO; PIN 8, 11 and 12 of DB25 are shorted (connected) Thus, we can simulate the above schematic on TIAO Universal Buffered Parallel JTAG Adapter. When should I buffer or terminate signals on a Joint Test


TJTAG | InfoDepot Wiki | Fandom Jtag is a program for fixing your router if it is in an otherwise unrecoverable state. Jtag is done with a cable hooked from a computer 25 pin printer port (USB might also be available) to an electrical connection on your router called a jtag port. There are sometimes two similar ports on a router; one is the jtag port and the other is a serial Introduction to JTAG - Embedded.com Oct 29, 2002

It is very important to have a strong ground connection between the JTAG controller and the board under test. If there are any spare pins on the JTAG connector to the board then adding extra ground signals will be beneficial. The XJLink2 has fixed ground connections on pins 10 and 20 so connecting these will improve signal integrity.

JTAG Hacking | Network World JTAG is actually a test point on a circuit board. It is a IEEE standard (IEEE 1149 Standard Test Access Port and Boundary Scan Architecture) that came about as a way to test circuit boards when we Programming microcontrollers: JTAG, SPI, USB oh my Still, the JTAG interface allows for the programming of an AVR which supports it. JTAG is an in-system debugging tool which allows you to manipulate and examine the status of a supported AVR while it is running in a circuit. JTAG allows the user to stop execution at any time, the manipulation of the AVR's internal registers and much more.