Issue with nRF-DTM when using Coded PHY

[macfly2000]

Issues.pdf

Hello,
I'm trying to use nRF-DTM between 2 DK nRF52840. I modified the firmware to have access to RSSI, things work well with 1Mbs or 2Mbs PHY. However, when I start to use Coded PHY S2 or S8, The issues are described in attached file. It's a very useful tool when trying to evaluate performances of different BLE modules.
Am I facing real bug and if so, do you see a way to solve them?
Thanks in advance for your time and support.

[olleheugene]

Hello,
I am so sorry.... I've just seen your comment.
It seems to bug in the tool. I will try to check the issue from tomorrow.
Sorry again too late answer and thanks for the issue details.

[olleheugene]

Hello,
I've checked your problem in both firmware and the nRF DTM tool and found the root cause.
The problem is I cannot set my own RSSI command with coded phy because Bluetooth core spec doesn't allow using the vendor-specific command with coded phy as below figure.

Even if I send the RSSI command over the vendor-specific command, the firmware will replace the type to 0xFF to fill the payload 0b11111111.
So, you need to change the firmware code allowing you to use vendor-specific packet type instead of coded phy type but, this is a violation of Bluetooth core specification.
I think you can modify the firmware source code just for testing RSSI of Coded phy. but I don't recommend you use the same firmware for certification.

Try with the below source code.

uint32_t dtm_cmd(uint16_t cmd)
{
...
#if defined(READING_AVG_RSSI)
if ((m_radio_mode == RADIO_MODE_MODE_Ble_1Mbit
|| m_radio_mode == RADIO_MODE_MODE_Ble_2Mbit
|| m_radio_mode == RADIO_MODE_MODE_Ble_LR125Kbit
|| m_radio_mode == RADIO_MODE_MODE_Ble_LR500Kbit
) && payload == DTM_PKT_VENDORSPECIFIC)
#else
if ((m_radio_mode == RADIO_MODE_MODE_Ble_1Mbit || m_radio_mode == RADIO_MODE_MODE_Ble_2Mbit) && payload == DTM_PKT_VENDORSPECIFIC)
#endif
...
}

Lastly,
I found a bug in the nRF DTM tool when I saw the problem you mentioned.
Thanks a lot! 👍🏼

[macfly2000]

Thank you very much Eugene for your time!