Multi packets in SDK 7.2.0 bootloader

[Gili Elias]

Hi, We are doing DFU updates through a nrf51422 dongle (data passing from UART to BLE), using our own code, based on the multilink central example.

The DFU peripherals are nrf51822, s110 7.0.0, SDK 7.2.0. The central unit is nrf51422 dongle, s130 3.0.0, SDK 12.2.0.

We are trying to achieve maximum throughput by using multiple packets per connection interval (@ 7.5 ms interval). It works fine when using a single packet and even two packets per interval, but when increasing to 3 or more, packets seem to get lost, even though TX_COMPLETE event is triggered.

Based on the peripheral SD and SDK, are they suppose to support such throughput?

EDIT: I can't seem to find a way to attach the sniffer trace file. The form allows me to select a file, but doesn't seem to do anything with the file I choose.

Try this link.

This is a trace with a 12 packet notifiaction and 4 packets per connection interval (connection interval set at ~18sec). I stopped it brutally at the middle since it was very slow. The 4 sec breaks are the time we wait for a notification on the central side.

[Hung Bui]

Hi Gili,

You are correct [0x10 0x03 0x06] tells operation failed when receiving image.

If you have a look at the release note of SDK v7 (known issue section) you can find that we only tested to work with minimum connection interval of 11.25ms. Most likely 7.5ms would be too short to do flash operation.

Could you try to increase the connection interval to 11.25ms and also change the packet notification to let's say 20 packets ? Make sure your central stops transmitting after every 20 packets to wait for the notification.