NRF52820 SDK_17.1.0_ddde560 DTM DEFAULT_TX_POWER ERR

[xiami]

Software 17.1
Engineering path: nrf5_sdk_17.1.0_ddde560 \ examples \ dtm \ direct_test_mode \ PCA10100E
I made a motherboard based on 52820.

I compile and generate hex, and then test the motherboard from Load to 52820. The test results show that the TX power is 3db, but the default TX power in the code is 0dB.

#Define default_tx_power radio_txpower_txpower_0dbm /** <default transmission power using in the dtm module.* /

I modify the default_tx_power to RADIO_TXPOWER_TXPOWER_Pos4dBm or RADIO_TXPOWER_TXPOWER_Pos8dBm, but the test results are 3db。

what should I do？

[Kenneth]

Hello,

If possible I suggest to use an nRF52-DK for comparison, but in this case it could be that the LE tester control the tx power used:
#define LE_TEST_SETUP_TRANSMIT_POWER     9     /**< DTM command control: Transmit power set. */

So it could be that the LE tester override the default configuration through using a LE test command, but that said, have anyone at Nordic reviewed your layout and schematic, if not it may be a good idea to create a private case and ask for a review.

Best regards,
Kenenth

[xiami]

I don't have nRF52-DK, but I made a motherboard based on 52840.
I use nRF5_SDK_17.1.0_ddde560\examples\dtm\direct_test_mode\pca10056\blank\arm5_no_packs
Compile the project to generate hex. After burning to the 52840 motherboard, test with the same method, and the test result shows that the transmit power is 0db.
I think the interference of LE tester and manual operation can be ruled out.

[Kenneth]

What if you use a parameter that is significant different such as: RADIO_TXPOWER_TXPOWER_Neg20dBm and RADIO_TXPOWER_TXPOWER_Neg12dBm, any difference?

Kenneth

[xiami]

I set DEFAULT_TX_POWER to RADIO_TXPOWER_TXPOWER_Neg20dBm and RADIO_TXPOWER_TXPOWER_Neg12dBm 。 The same test results show that the tx power is 3db。

[Kenneth]

You are sure you are programming the board correctly? Does this work as expected if used on any other board?

Kenneth