LAUNCHXL-CC2640R2: Custom Designed Board Bluetooth Connection Problem

Hi,

Your Schematic looks ok to me.

Did you do any RF tests on your board?

If not please do some basic tests (Tx power test, Freq accuracy, PER test) by using SmartRF Studio. 

You can use CW-Unmodulated mode for Tx Power test and Frequency accuracy test. You may need to use Cap Array tuning for better Freq Accuracy. Please refer to SWRA640 for further details. The following is the link to SWRA640.

For PER test, you can put one board in Packet in Tx mode and the board in Packet Rx mode.

You need to interface your board to the Launchpad (by using JTAG Connector) to use SmartRF Studio. Also please remove all the Jumpers on the Launchpad from the IO connector (Middle of the LP with the lot of Jumpers).

Why did you change "#define CC2650EM_7ID" line with the  "#define CC2650EM_4XS" line in CC2640R2_LAUNCH.h file ?

4XS is 4*4 package and has different Pin Out to 7*7 package. It seems you are using 7*7 package. So, this may not be correct.

Thanks,

PM

PM said:

Why did you change "#define CC2650EM_7ID" line with the  "#define CC2650EM_4XS" line in CC2640R2_LAUNCH.h file ?

4XS is 4*4 package and has different Pin Out to 7*7 package. It seems you are using 7*7 package. So, this may not be correct.

Just a reminder with regards to these defines at CC2640R2_LAUNCH.h

* CC2650EM_7ID - Differential RF and internal biasing
(default for CC2640R2 LaunchPad)
* CC2650EM_5XD – Differential RF and external biasing
* CC2650EM_4XS – Single-ended RF on RF-P and external biasing
* CC2640R2DK_CXS - WCSP: Single-ended RF on RF-N and external biasing
* (Note that the WCSP is only tested and characterized for
* single ended configuration, and it has a WCSP-specific
* PA table)

Hi,

My custom board schematic has the whole peripheral with the launch board except RF schematic. Since the launch board's RF schematic is  Differential RF and internal biasing as you said but I designed my card as Single-ended RF on RF-P and external biasing RF schematic. Because of that, I used "CC2640R2_LAUNCHXL" defined board files but "CC2650EM_4XS" RF configurations.

So, if I could implement correctly, this method should work I think.

Thanks for your reply.

Dogus

Hi Genius,

I tested just like you said about replacing CC2650EM_7ID and CC2650EM_4XS. I tested with CC2650EM_7ID and still the same problem. Also, I tested with "#define CC2650EM_7ID" and making my RF schematic "#define RF_FE_MODE_AND_BIAS ( RF_FE_SINGLE_ENDED_RFP | RF_FE_EXT_BIAS )" in ble_user_conf.h and stil the same problem.

I will also make the test you said with SmartRF studio. I will share my results here asap.

Thanks,

Dogus

Hi,

If your RF configuration is Single-ended RF on RF-P and external biasing then you should set define CC2650EM_4XS.

I suggest you request your PCB design for review by TI Engineer.

-kel

Hi,

Please test your board with SmartRF Studio and let me know the result. If that is OK then I will refer you to one of our Software engineer to help you with your code.

Thanks,

PM

Hi,

I tested my card with SmartRF Studio with these configurations;

and I tested my board with different channels (frequencies) and with different TX powers. Here are my results;

I repeated PER test several times for each BLE Channel (both receiving and sending) and the results are average results.

In the red part above, when I start the "Packet RX" mode at the launch board side, It receives 100 packets from other devices in my office I think because I could not press the Start button at Custom Board Packet TX mode in the meantime.

Here are my results, if these outputs do not help you to give a clue of the problem, I am ready to do some other tests you advice or share PCB and software project directly with TI engineers.

Thanks,

Dogus