JTAG, power supply.

[luiHS]

 
Hello

What is correct, that a programmer by JTAG provides supply voltage for pins 1 and/or 2, or that it receives supply voltage for any of those pins?

I have been connecting my RT1020 and RT1050 evaluation boards, with Jlink SEGGER and Multilink PE micro. The Jlink gives 3.3 volts for the pins 1 and 2 of JTAG, whereas the Multilink does not give voltage for any of those pins.

The problem is that when I have connect the Jlink to the evaluation board RT1020, at first it worked, but when I have press the SW5 button on the board, which I think is to do a RESET, the board has stopped working, and now it has shorted the pin 2 (JTAG_PWR) with GND of the JTAG connector.

According to the diagrams, of the 4 push buttons, SW4 is for user applications, SW2 (ONOFF) is for RESET directly to the microcontroller, and only the SW5 and SW3 buttons act by doing some type of reset, I do not understand why so many reset buttons.

SW5 goes to an NTSX2102 chip, which is a bidirectional voltage converter, and SW3 goes to a UM805 chip, which is a voltage monitor with manual reset option.

In the board that I have with the RT1050, I have not yet pressed any button, and I'm afraid to press any (SW3-SW5), using the programmers by JTAG, at least with the Jlink that is the one that gives 3.3v voltage for the pins 1 and 2 of JTAG.

[luiHS]

 
It seems that my (chinese) Jlink programmer is defective or damaged, because on the Segger website about the Jlink programmer, pin1 is input to the voltage reference and pin2 is not connected. Also from NXP they suggest that this is the problem.

https://www.segger.com/products/debug-probes/j-link/technology/interface-description/

1   VTref   Input   This is the target reference voltage.
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.

2   Not connected   NC   This pin is not connected in J-Link.
It is reserved for compatibility with other equipment.
Connect to Vdd or leave open in target system.


When I use Jlink to program / Debug by SWD with Kinetis microcontrollers, it works fine, but I only use a 5-pin connector, with GND, SWDCLK, SWDIO and 3.3v external supply for the board. I never used the 20-pin JTAG connector, until now, with the RT1020 / 1050 evaluation boards, and this has burned the RT1020 board.

I will use for now my programmer Multilinik PE, this works well, there is no power output in pins 1 and 2, and pin1 works as input because a led of the programmer is turned on when connecting it to the board and receiving power supply voltage that pin. I also have another Jlink, EDU version, but with limitations regarding the professional version.