RE: Lab Certifications / test-modes / DTM

Simon Third — Thu, 05 Jun 2014 23:33:26 GMT

Hi,

I have recently setup units for testing at the lab. You will need to send them standard units with FW that will be shipped with the unit. You might also need to provide equipment that uses the link so that all functions are on (with the most EMC/I generated).

Because your product is an intentional radiator, and the module has other HW around it, or different antenna connections layout, the transmitter and receiver (for local oscillator emissions) RF need to be remeasured. Depending on what the lab requires you might need to supply a unit with a test coax on the 50ohm point of the antenna output also for conducted RF tests.

DTM (Direct Test Mode) is a stand interface for Bluetooth test tools to perform RF PHY tests, but is also most convenient to implement a test setup for your lab that enable continuous Tx/Rx on tests. See Volume 6, Part F of the BT4 core spec for more DTM protocol info.

The easiest way for you to set up these units is to build the DTM example project, load the RF test units with that and wire up a USB to 232 TTL cable to your UART pins. You could give the lab nRFgo Studio as the PC end interface to DTM or write your own PC app.

I've included DTM in my product apps to enable PCBA RF Tx tests in the factory, which is also based on the example.

Simon