DTM test between two nrf51822 chips?

[Husky_xc]

Hi,

In my project, I only have PCBs with nrf51822 chips and do not have a plan to buy a spectrum analyzer yet. But the certification requires me to apply DTM application to my chip and I don't know if I click the button on nrfgo studio is the code actually working or not....Is there any suggestions?

Can I apply DTM application to two PCBs and use one in tx test mode and another in rx test mode? Can I see any number change on nrfgo studio in this way?

Another thing is, I changed TX/RX pin number and compiled from Keil\dtm\direct_test_mode\pca10028\blank\arm5\direct_test_mode_blank_pca10028.uvoptx , then load the this hex file directly to (blank) nrf51822 chip without any softdevice/bootload.

Is that the right way to do?

Thanks

[endnode]

You can easily run DTM between two nRF5x chips/devices. The FW example from SDK doesn't use Soft Device or other stack, it accesses Radio interface directly. If you are sure that your UART PINs match your HW configuration and you are able to convert this UART to be able to plug it to PC (e.g. FTDI RS232 3V3 TTL to USB cable does the job) then simply set-up Python test scripts from Nordic application note and you are done!

[Husky_xc]

Thanks for the quick answer! I checked the link you shared above, hmm..I don't have access to any coaxial cable from my customized PCB and I don't have a nrf51822 development kit with me... only two customized PCBs with nrf51822chip and embedded wireless antenna. Any suggestion?

[endnode]

Sure, simply get out two PINs on each board (this is kind of a must, without that you would need to rewrite whole DTM thing significantly) and connect or solder them to Tx/Rx PINs of such cable.

Not sure what you mean by "coaxial cable", no one asks you for that one;)

[Husky_xc]

Oh, I was looking at the picture Setup with PCB module with SMA connector as Lower Tester in nAN34 Setting up production test using DTM file. So what you mean is I can connect my 2 PCBs to PC using 2 Serial to USB cables. and then run the python script on my pc, without any wired connection between two PCBs? And then just run the python script? Thanks, man!

[endnode]

Sure, that's how all we do it. nRF5x Dk boards have built-in COM ports through SEGGER J-Link OB chip and FW so it is even easier, but if you know how to connect Serial to USB cable it's still piece of cake (don't forget to connect the ground;) Finally there is a limitation in whole DTM set-up: it should be probably done in isolated environment and Faraday cage with proper vias for UART or USB cables which shields in 2.4GHz range properly can get really expensive. But for the first feeling you can run it on free air without big problems (also note that former Nordic DTM examples had bugs in proprietary commands for setting Tx Power, I hope they fixed it or you are fine with default Tx Power set in the FW - used to be max +4dBm but for some strange reason they lowered to 0dBm since certain SDK release). Good luck!