lpcware

Requirements for stand-alone SWD connection to LPC11U14 target board

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by stanimir on Wed Oct 09 12:06:38 MST 2013
Hello,

I'm trying to connect the target part of the LPCXpresso to a SWD debugger. I was going to use JTAG but after a while I realized it can not be used as debugging interface, so I wen to try the SWD connection.

Here is what I did and didn't have any success. I tried with CrossConnect and ARM-USB-OCD debuggers in SWD mode.

1) I disconnected Link and Target boards by desoldering the pads in the middle of the J4 connector (the one between the two boards)
2) Made a cable between 20-pin header of the debugger and J4 part at the LPC11U14 target board with the following pins (as written in the Kit's schematics):
GNDX, JTAG_RESETX, JTAG_TDIX, JTAG_TDO_SWOX, JTAG_TCLK_SWCLKX, JTAG_TMS_SWDIOX

3) Powered the target board with 3.3V from external power supply
4) Connected debugger with the cable from 2)
5) Tried to connect using CrossStudio, both with their CrossWorks (JTAG/SWD debugger) and ARM-USB-OCD without any luck

What am I missing? Is there a problem that the SWD pins are not pulled-up, but connected straight to the debugger?
I checked that the signals are going to the board, also RESET is always HIGH. When trying to connect I see that the debugger is sending something trough the SWCLK and SWDIO but nothing after that.
Should I connect 3.3V between debugger and mcu or using external (grounded with the debugger) power supply is ok?

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