Hey there,
today I'd tested around with the Dfu service.
- Peripheral is nRF51822 running Sdk 5.2.0 bootloader example (Softdevice 6)
- Central is Android 4.3 running nRF Mcp 1.9.1
- Testfile (nRF51822 Application) is Hrs Example (about 43k binary size)
In the settings of Mcp I found some Dfu options and I determined that the »Number of packets« value has an affect to the update data throughput.
My Android device connects with 48,75 ms connection intervall and transferes mostly about 4 packets at each connection intervall. So, the max throughput is theoreticly at
4 x 20 Byte / 48,75 ms = about 1.641 Byte/s
But when metering the Dfu throughput, I got just about 1.000 Byte/s. Well, after changing »Number of packets« from 20 to 300, I got about 1.600 Byte/s - nice.
But then, when I set »Number of packets« to greater values (e.g. to 400), the Dfu upload freezes at 16 % - and the same when I switching off the option »Packets receipt notification procedure«.
For »Number of packets«, I determined a treshold value of 356. This means that Dfu works with values up to 356, but for greater values the Dfu freezes at 16 %.
Ok, I don't expect higher throughput with higher »Number of packets« values. I'd just detected that issue and would report it.
Btw: Is this the right place for that kind of topics or should I rather put that in an issue tracker?
