CC2540: Not seeing data packets in the sniffer trace/log

s d1

Part Number: CC2540

Hi,

I'm using USB dongle to sniff BLE packets. I could see advertising data but its all the same. How can I view actual raw bytes being sent?

In the bottom window, I tried to view data under Packet details but its just another copy.

Thanks!

over 6 years ago

0 YiKai Chen over 6 years ago

Guru 735685 points

Try to refer to www.youtube.com/watch and www.youtube.com/watch

0 s d1 over 6 years ago in reply to YiKai Chen

Prodigy 70 points

I have watched both these videos already. I cannot see the data packets, I can only see the advertising packets. My BLE device is the peripheral and Windows PC is the central. Windows machine is receiving data continuously from BLE device but its the TI sniffer which cannot see this data.

0 YiKai Chen over 6 years ago in reply to s d1

Guru 735685 points

A CC2540 dongle can only sniffer one channel so you can try to fix your BLE device to advertising on channel 37 only and sniffer channel 37 to see if it works.

0 s d1 over 6 years ago in reply to YiKai Chen

Prodigy 70 points

Ohh so you mean to say that the BLE device should advertise & send data over same channel 37?

0 YiKai Chen over 6 years ago in reply to s d1

Guru 735685 points

That's only for your convenience to sniff BLE advertising and connection. The alternative is to use 3 different CC2540 USB dongle to sniff on channel 37, 38 and 39 at the same time.

0 Marie H over 6 years ago

TI__Guru* 81491 points

Hi,

In order to see data packets you need to make a connection between two BLE devices. You can read how to configure the Packet Sniffer to follow a BLE-Connection in the Packet Sniffer User's Guide.

0 s d1 over 6 years ago in reply to YiKai Chen

Prodigy 70 points

I tried to sniff all channels but couldnt find any data packets. I'm not seeing even the empty PDU packets.

Should I see any packets as shown in the attached image? If yes, I couldnt see anything besides advertising data.

0 s d1 over 6 years ago in reply to Marie H

Prodigy 70 points

Yes after the BLE connection, the software running on the host/central machine is receiving data packets over BLE. Can you please share the link for User guide, just to make sure I'm referring the same one.

0 s d1 over 6 years ago in reply to Marie H

Prodigy 70 points

Ohh and just to let you know I'm even entering the intiator's address i.e. my laptop's address.

0 Marie H over 6 years ago in reply to s d1

TI__Guru* 81491 points

Hi,

There is an element of "luck" since the sniffer needs to catch the CONN_IND packet in order to start following a connection. It's not unusual to have to try a couple of times.

You can configure your peripheral device to only advertise on one channel (e.g. 37), and configure the sniffer to monitor the same channel. This way you know the CONN_IND packet will come on the channel you are sniffing.

0 s d1 over 6 years ago in reply to Marie H

Prodigy 70 points

Hi Thanks, I'll definitely try this.

I had one more question - Can this module sniff BLE packets in general or its just something specific to TI BLE chip?

0 YiKai Chen over 6 years ago in reply to s d1

Guru 735685 points

It can sniff BLE packets in general.

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CC2540: Not seeing data packets in the sniffer trace/log