HCIExt_SetTxPower does not seem to have any effect

Reto Truninger

Other Parts Discussed in Thread: CC2540

I've got two CC2540 USB dongles and one Keyfob. One USB dongle has the HostTestRelease firmware and the other has the packet sniffer loaded. The Keyfob has the KeyFobDemo loaded. I use BTool to connect to the Keyfob. With the packetsniffer I'm looking at the RSSI of the packets sent from the dongle. Now I use BTool to change the Tx power level using the HCIExt_SetTxPower command. The command completes successful, but I can not ever notice any difference in RSSI on the packet sniffer. I expect that I would see a big difference of the RSSI if I switch form +4dB to -23dB.

For this test I used all the original software without any modification as it comes with the BLE 1.1 release. Any ideas what might be wrong?

over 14 years ago

0 Willis1 over 14 years ago

TI__Genius 17975 points

You definitely should be seeing a change in the RSSI, though I can't really tell what you are doing wrong. When you change the Tx power in Btool, do you get a SUCCESS status in the returned event?

0 Reto Truninger over 14 years ago in reply to Willis1

Intellectual 535 points

Yes, Btool reports success. I loaded the old HostTestRelease from version Version 1.0 (October 7, 2010) onto the dongle and it works fine! I can set the Tx levels and see the RSSI change in the sniffer as expected. If I use version Version 1.1 (July 13, 2011) it doesn't work, no change of RSSI. It seems to have been broken in this version for some reason. Also I tried to call HCIExt_SetTxPower directly from my code and without any success either (I haven't tried this using V1.0). Could you please follow this up, the problem seems easy to replicate. Also am I using the latest version?

Thanks

Reto

0 kazola over 14 years ago in reply to Reto Truninger

Guru 18595 points

Hi Reto,

the latest version is 1.1a, released in Aug 10, 2011, but no Software Developer's Guide was released that date and not so many users have noticed the change. The README file shows the release notes according to what I'm telling you. You can download the new version it from this link even if Texas Instruments has an issue with the SSL certificate ;)

Perhaps you could check if your problem is solved in this new version?

0 Reto Truninger over 14 years ago in reply to kazola

Intellectual 535 points

I've tried 1.1a with the same result as 1.1. So it does work with 1.0 but not with 1.1 or 1.1a. I've tried different hardware all the same result. Would it be possible for somone at TI to test this, since this is a big issue for me.

0 Brecht Van Cauwenberghe91702 over 13 years ago in reply to Reto Truninger

Prodigy 40 points

I'm experiencing the same problem as Reto Truninger has described.

When call the function HCIExt_SetTxPower in SimpleBlePeripheral from the 1.1a stack and i see no changes in RSSi value in SmartRF Studio 7.

When i use the BLE 1.0 stack the RSSi value changes as expected.

Was there any recent feedback on this topic?

Any ideas what could be the cause of this problem?

0 Reto Truninger over 13 years ago in reply to Brecht Van Cauwenberghe91702

Intellectual 535 points

Hi Brecht

I haven't got any more feedback from TI regarding this. It's still not working and I'm pretty much sure this is a bug introduced into the 1.1 stack, specially since it is so easy to replicate using BTool. It would be very much appreciated if someone at TI could try to replicate the problem using BTool and confirm our findings and investigate the bug. For now I'm using the standard tx power setting (0dBm as far as I remember) and I hope this will be good enough for my project.

Reto