Production line testing of CC256x Tx

Hi,

In CBT I have not see this issue.
anyway I think you are getting this issue, As your tester did not receive sufficient measurable packets to complete the selected test. 

Did you check the setting of the tester properly. Like setting the "Number of packets" to minimum, TX_Channel.

Dear Sundeep,

yes, I checked all the settings. The CC256x should be in continuous TX mode, so the tester should get enough packets back. TX_channel is also configured correctly (is simply used the default channel 0 at 2402 MHz).

Could it be that a wired RF connection is required from the C256x to the tester for TX testing? 

My CC256x is actually connected through the wired serial (HCI) port to the tester, and in parallel to that, through a wireless RF connection.

Best regards,

Severin

Hi,

I don't think I fully understand your question.

Anyway let me answer from what i understand.

The CC256x BLE device (possibly interfaced with host MPU/CPU) is connected to the PC which communicates with the CC256x by sending specific HCI commands using UART 8-N-1 serial protocol. The CC256x is also connected to the tester which is the CBT Bluetooth Tester via U.FL/SMA connector.  

see: http://processors.wiki.ti.com/index.php/CC256x_Testing_Guide#BLE_Testing

Dear Sundeep,

I did exactly what is explained on the TI website on BLE testing that you mention.

In my setup, the connections between the CC256x and the tester (Anritsu MT8852B) are the following:

1) wired HCI connection

2) RF connection

I believe the RF connection can be replaced by a cable (conducted RF). While this is the recommended setup, it is not a must..

Again exactly as on the website, I can issue HCI command to the CC2564 in order to set up the test parameters (0xFD77) and to start TX test mode (0x201E). By the way, on http://processors.wiki.ti.com/index.php/CC256x_Testing_Guide it incorrectly says the command is 0xFD74 for setting the test parameters !! It is 0xFD77 as said on http://processors.wiki.ti.com/index.php/CC256x_VS_HCI_Commands.

Once the test mode started, I should be able to observe transmission on a specific channel and with a specific type of packets (I can configure an unlimited amount of packets). However, with the MT8852B I cannot detect any trace of anthying being sent. On the other hand, the CC2564 acknowledges both commands 0xFD77 and 0x201E, so I suppose that it entered the correct mode of operation.

I really do not know where to look for the problem.

Any help appreciated,

Severin

Hi,

It is preferred to do this test conducted rather than radiated to avoid interference. But it is not a must if you can make sure that interference is not an issue.

Yes you are right, it should be 0xFD77. The 0xFD74 might have come from older revisions of the device, we will update the wiki.

Could you check with a Spectrum Analyzer if there is TX activity.

also could you please test it at High input level.

Hi,

I have the TX tests running now, with an over-the-air link rather than with a cable and conducted RF. I will probably use a shield box at the end in order to exclude interference with other Bluetooth devices.

My original probelm with the TX tests was in the configuration of the CC2564 at startup (service pack etc.).

It seems that I need to be in RF SIG mode !? I thought this was not relevant for BLE testing?

If I do not issue the three commands for entering RF SIG mode, as outlined on http://processors.wiki.ti.com/index.php/CC256x_Testing_Guide, I cannot get the command "HCI_BLE_Transmitter_test" to work.

However, once in RF SIG mode, all three TX and RX tests work fine with my Anritsu MT8852B tester.

Could you please explain a bit why entering RF SIG mode is necessary?

Best regards,

Hi,

I think you for connecting to the tester you need to enter the RF SIG mode.

http://processors.wiki.ti.com/index.php/CC256x_Testing_Guide#BT_RF_SIG_Mode 

Hi,

yes, of course I am aware of the RF SIG mode section on the webpage you mention. 

However, the section for Bluetooth Low Energy testing is clearly not making any reference to the RF SIG mode section. 

Therefore, I thought that entering RF SIG mode is not required for Bluetooth LE testing.

In the RF SIG mode section, it says:

"Once the device (DUT) is in test mode, the BT tester will, through the RF connection (LMP), take control of the DUT. "

This is clearly NOT the case for BLE testing....

If RF SIG mode is required for BLE testing, then please add a reference in the BLE section of the webpage.

Thanks,

Severin

Hi,

Thanks you very much for you time and inputs. 

I will take it with the respective team and make sure that they do the needful.

Thanks once again we really appreciate you inputs.