Reset issue when linking CMW270 with DTM

[SHMoon]

hi

We are conducting SIG certification testing with nRF52832 and DFM.

(CMW270)

The TX test was completed normally.

However, a problem occurred in the RX test.

The problem with the RX test is that if you try to change channels, the nRF52832 resets.

* composition

CMW270  ---- (USB port)  ----- CP2102 PCB (USB to uart, 5V power source )  --------(UART, DC 5V)-------- nRF52832 PCB ----- (SMA) ------ spectrum analyzer

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* Estimating the cause of the problem
1) DC 5V power drop delivered to USB port? (But the TX test has been completed... so the probability seems low)

2) RX buffer size insufficient?

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Is there anything to review?

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Additionally, when running DTM in nRF Connect for Desktop, both TX/RX operate normally.

nRF Connect for Desktop does not allow settings below "Receive Period = 30ms"...

Are these settings necessary in the actual CMW270?

thank

[ovrebekk]

Hi 

If I understand your description properly, the UART interface to the nRF is running at 5V? 
This could be a problem, as the voltage is outside the legal range for the nRF52832, and could lead to unpredictable behavior.

Could you try again with an adapter that can provide a UART voltage similar to the nRF52 supply voltage? 

Best regards
Torbjørn

[SHMoon]

Hi

Thank you for answer.

- nRf52832 receives DC 3.3V from CP2102 PCB

- When measuring the voltage level of the rxd and txd communication lines of CP2102 PCB and nRF52832 PCB, the measurement experiment is 3.3V.

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https://resources.altium.com/p/cp2102-usb-uart-module-pcb-design-project

Looking at the data above, cpe2102 creates VDD through USB power (VBUS), and the rx and tx voltage levels operate based on this VDD.

Therefore, it does not seem to be a 5V problem on the communication line.

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Additionally, Looking at the detailed symptoms

In tx, it operates normally even when moving the first channel and channel.

In rx, the first channel operates normally, but when changing channels, a reset occurs.

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Just in case... would it make sense to try changing the UART to USB PCB to one with a different chipset?

Currently it is cp2102, but other chipsets such as FT232 have been applied...

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thank.

[ovrebekk]

Hi 

Could you try to enable logging in the direct_test_mode firmware (over RTT), and see if you get some crash log when the issue occurs? 

Then it should be easier to investigate what the root cause is. 

If you do, please include the log in the case so I can have a look at it. 

Best regards
Torbjørn

[SHMoon]

Hi

I set the settings as below again, but it failed to receive RTT log.

#define NRF_LOG 1   // add

#if NRF_MODULE_ENABLED(NRF_LOG)

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And I did an additional experiment.

RX is received from the DTM of nRF Connect for Desktop.

Through SMA, we sent a packet from an external device and checked whether it was received through DTM reception of nRF Connect for Desktop.

However, the result was that reception was always 0.

Are there any settings that need to be adjusted on the device that sends data packets externally via SMA?

[ovrebekk]

Hi 

My bad, I now realize there is no logging support in the direct_test_mode example, so it makes sense that it wouldn't work. 

SHMoon said:

Are there any settings that need to be adjusted on the device that sends data packets externally via SMA?

By SMA I assume you mean the J1 connector on the DK? 

If you connect a cable to this connector the antenna signal should be switched automatically, to go to the connector rather than the DK antenna, so no configuration should be needed. 

Best regards
Torbjørn