CC2640R2F: custom board Hardware problem, downloading, ble connecting failure.

gyungmin lee

Prodigy 60 points

Part Number: CC2640R2F
Other Parts Discussed in Thread: LAUNCHXL-CC2640R2

I have some problem with CC2640R2F.

I made about 20 boards.

Sometimes it was not downloaded. (Unrecognized - Debugger xds110)

actually I use LAUNCHXL-CC2640R2

The other board advertised but could not connect.

But one of them works normally.

Please let me know how can I fix it.... I'm in hury

over 7 years ago

0 YiKai Chen over 7 years ago

Guru 735695 points

Try to refer to CC26xx HW Troubleshooting.

0 gyungmin lee over 7 years ago in reply to YiKai Chen

Prodigy 60 points

Already ....I tried to CC26xx HW Troubleshooting...
I want you to watch the pcb layout....

0 Simon J over 7 years ago in reply to gyungmin lee

TI__Genius 11810 points

Hi Gyungmin,

If possible, can you upload the gerber files?

1. Have you connected the pad of the CC2640R2F to ground? The screenshot don't show any vias there.
2. Do you have a ground plane on layer two?
3. How is the blaun connected to gnd? It looks like it's connected with only one single via?
4. Are you using via in pad on many components? Otherwise many of the components, like some of the decoupling capacitors, may have inadequate connection to gnd.

Best regards,
Simon

0 gyungmin lee over 7 years ago in reply to Simon J

Prodigy 60 points

4520.PCB.pdf

Thank your word...

1. yes, there is a single via in pad

2. it is 2-layer pcb(as you can see pdf file)

3. balun is connected to gnd through the via

4. I think routing to gnd seems to be fine....because I checked connectivity....

0 Simon J over 7 years ago in reply to gyungmin lee

TI__Genius 11810 points

Hi Gyungmin,

Thanks for the pdf, that makes it easier to review the layout. Some concerns:

- The pad is connected to gnd with a single via. This creates a high impedance current return path. We use 16 vias (in parallel) on our reference design to achieve a low impedance return path.
- Try to use a solid ground plane. All the tracks on the bottom layer create a very long ground return path from the RF components, DC/DC converter and decoupling capacitors to the chip. It looks like some return paths are through more than one via (i.e. vias in series). This causes high impedance return paths.
- The ground return path for the balun to the pad must be uninterrupted. Also, more than one via is beneficial.
- Note that connectivity in the CAD tool is not equal to good RF connectivity.

See this presentation for more details: processors.wiki.ti.com/.../CC26xx_HW_training_Layout_Considerations.pdf

Also, have a look at our reference designs: www.ti.com/.../toolssoftware

Best regards,
Simon

0 gyungmin lee over 7 years ago in reply to Simon J

Prodigy 60 points

Thank you Simon

I appreciate you to help find solution.

Several boards work by successfully soldering But it still has not stabilized.

So I will try to build a new pcb according to your advice.

Your advice has been a great help to me.

Thank you Simon

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CC2640R2F: custom board Hardware problem, downloading, ble connecting failure.