I am developing an application using the Bluetopia V1.21 Stack, MSP430F5335 processor, and CC256X radio.
I have been experimenting with the stack settings while trying to optimize SPP performance when communicating with various cell phone platforms. Communications is reliable when using the default SPP frame, tx buffer, and rx buffer settings of 38 bytes. I have increased the frame size to the maximum of 50 bytes which works reliably. If I increase the tx and rx buffer sizes much above 120 bytes, communications becomes unreliable with a Motorola Razr (Android OS V2.3.5) but continues to work reliably on a Samsung Charge (Android OS V2.3.6). If I continue to increase the rx and tx buffer sizes, the Samsung Charge begins to fail with buffer sizes around 240 bytes.
The main symptoms are a failure to receive an etPort_Data_Indication event when data is received or a failure to send data when SPP_Data_Write() is called. SPP_Data_Write() returns the proper number of bytes when called.
Our protocol uses packets as large as 255 bytes so a buffer setting of 256 bytes seems ideal. The difference in the thresholds between the two cell phones is a bit puzzling - this makes the problem appear as if it is not a memory related issue.
Thanks,
Mike
