BC127 cannot consume all data in high speed mode

Hi,

BC127 FW Ver.: 6.1.8RC3
UART Config:   921600 ON 0

In out application, I send a continuous stream 26kBytes/sec to Android/iPad in high speed mode.

In iPad(iOS), all data is sent and consumed by BC127.

in Android(Phone or Tablet), there are UART flow control to denied data transfer.

I have gone through the configs not much I can change for SPP parameters.

We also do a term monitoring, after 30min, the SPP choke disappears.
This problem can also be replicate on BC127 EVB.

Best,
Brett

Brett,

iOS does not support SPP so what profile are you sending it over? What are you sending it to i.e. app?

Regards

Matt

Hi Matt,

For iOS, I am using iAP profile. I was assuming iAP is based on SPP profile with Apple encryption.
App is our own app, it has the same behavior in Melody app.

Brett,

From what I can discern iAP is more than SPP with encryption so it probably operates in a completely different way which means the two are not really comparable.

Regards

Matt

Thanks for the clarification.

Then the problem is narrowed that in SPP connection, a 26kBytes/sec stream should be able to transmitted by BC127.

The transmission behavior is every 8ms, send out 208 bytes.
From the spec, the bandwidth is 1.6Mbps. It should be enough for this size of data.

Or there are some suggestions for sending stream of data into BC127?

Best,
Brett

Brett,

I think I can see the CTS line toggling during a transmission (even though my unit is running with a UART speed of 115200), equally the data gets to the other side reliably. With regards the actual data rate in all wireless tech you need to take the max theoretical, cut it in half and this is what you would probably see in reality.

You are going to need to push this back through your commercial channel to have it raised to the dev team to see why this is the case as I don’t know.

Regards

Matt

Matt,

I am also working with commercial channel to push back this issue.
Since in the manual, it states the SPP high speed mode has 700kbps bandwidth.
I think stream at 26kB/sec,less than 1/3 of the peak speed, should be OK.

Other the other hand, iAP can handle this data with 500kbps bandwidth stated in manual.

I am guessing maybe buffer behavior is a little bit different. Or if there’s a sample script for performance testing, I can check the max bandwidth with EVB.

Best,
Brett

Brett,

Did some more testing, took the UART upto 460kbps and was getting 160kbps out of the unit, performance seems to level out here (not a huge difference between setting the UART to 230 or 460) so either this is where the limit is practically or there is a bottle neck either in the app, BC127 or the UART link itself.

As a rule anyone driving data rates over 115200 goes USB because serial links start to get unreliable beyond this.

Regards

Matt

Hi Matt,

Did you enable HISH_SPEED and also UART with flow control? 160kbps is 20kBps which is lower than what I have already seen.
Though there’s some loss problem on SPP, the flow is still having ~205kbps.

I am still curious about the 700kbps in SPP and 500kbps in iAP. if in real case or no setup can achieve or close these numbers, the spec/manual should be modified.
Or indicate the numbers are in USB mode.

Best,
Brett