CC2640 Debugging with JTAG

Senthil Natarajan

Other Parts Discussed in Thread: CC2640

Hello all,

I've just recently gotten started learning about setting up JTAG debugging. I've got a cc2640 RHB package.

I'm trying to set up JTAG debugging for it. After reading around, I decided to go with the XDS100v3 and use 4 wire JTAG. I'm using a 14 pin header from SAMTEC, and looking at the pinout specified by TI in the image below.

It's pretty easy to understand how to wire the GND pins, TCK, rTCK, TDI, TMS, TDO, and VTRef. However, I'm confused as to how to wire the other pins - EMU0, EMU1, KEY, TDIS, nTRST, nor do I fully understand what they are for. I'd appreciate a little bit of help/clarification in how to set this up.

Thank you!

over 8 years ago

0 Fredrik K over 8 years ago

TI__Guru** 106705 points

Hi Senthil,

The only required signals are: TCK, TMS, TDI, TDO, RST, as well as VDD_sense and GND. As the XDS100v3 supports cJTAG you can even omit TDI and TDO. I recommend using the 10 pin Cortex Debug header as it is smaller and simpler.

Cheers,
Fredrik

0 Senthil Natarajan over 8 years ago in reply to Fredrik K

Prodigy 40 points

Thanks a lot! That really does simplify things. I've switched to a SAMTEC FTSH header for connecting to the Cortex 10 pin debugger. The footprint is a lot smaller too, which is nice. Just to clarify, is the RST signal from the JTAG routed to the RESET_N pin on the cc2640?

0 Fredrik K over 8 years ago in reply to Senthil Natarajan

TI__Guru** 106705 points

Yes, RST from JTAG/Debugger goes to RESET_N on CC2640.

Cheers

0 Matt Staniszewski82 over 8 years ago in reply to Fredrik K

Prodigy 80 points

Hey guys,

Thanks for posting this, it's been super helpful! We are also using the CC2640 with 2-wire JTAG and the XDS100v3. A few additional questions, does the VDD_Sense connect to the target power or the debug tool power? Are there any pull-up/pull-downs needed on any of the signals? Here's my current pinout:

Thanks again!

Matt

0 Fredrik K over 8 years ago in reply to Matt Staniszewski82

TI__Guru** 106705 points

Hi Matt,

VDD-sense connects to the target power (it drives the internal level shifter in the debugger). No pull is required on the signals.

Cheers,
Fredrik

0 Matt Staniszewski82 over 8 years ago in reply to Fredrik K

Prodigy 80 points

Thanks Fredrik, much appreciated.

So there isn't a pull-up needed for RESETn? I'd figure it would need one. Also, attaching target power to pin 5 in my figure above, does that pinout look correct?

0 Fredrik K over 8 years ago in reply to Matt Staniszewski82

TI__Guru** 106705 points

You are right, RESETn requires a 100k pull-up.

I am not sure what pinout you are following, but I recommend using the 10-pin Cortex Debug header.

0 Matt Staniszewski82 over 8 years ago in reply to Fredrik K

Prodigy 80 points

Thanks Frederik, I was planning on using the standard 14-pin TI layout for my header. Any need for a cap to GND on the reset line as well? I saw some references to needing one in addition to the pull-up.

Matt

0 Fredrik K over 8 years ago in reply to Matt Staniszewski82

TI__Guru** 106705 points

Hi Matt,

We have it in the reference design, but to be honest I am quite confident you will be fine without it.

Fredrik

0 Matt Staniszewski82 over 8 years ago in reply to Fredrik K

Prodigy 80 points

Thanks Fredrik, looks like I'm all set!

Matt

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CC2640 Debugging with JTAG