Sending data bigger than 20 byte with ble

RE: Sending data bigger than 20 byte with ble

Ulrich Myhre — Thu, 04 Feb 2016 12:29:22 GMT

My answer was based on the SDK that was available then, and might not be that relevant anymore. The DFU examples still have good examples for recombining data and writing it to flash. To fragment the data, you simply send 20 byte chunks until you are out of buffers, increasing the pointer of the first byte by 20 every time the send is successful. Then you wait for a TX_COMPLETE event and re-do the operation. The packet count in that event is an ACK that the peer has received that many packets. On the peer side you need to either store the data in a temporary buffer, or immediately write it to UART or flash. It will come in the order it is sent, so this is a fairly simple operation.

Since this question is already answered and accepted, your question might not get the attention it deserves. Feel free to raise a new question if this didn't solve your problem.

RE: Sending data bigger than 20 byte with ble

Victor — Thu, 04 Feb 2016 10:46:08 GMT

May I ask you to directly link to the example in the answer, please?

RE: Sending data bigger than 20 byte with ble

Nguyen Hoan Hoang — Thu, 04 Feb 2016 03:51:53 GMT

There are links to the github repo. It is multi-platform code supporting NXP, Nordic, Freescale, TI. There are shared generic source for all and specific for each MCU.

RE: Sending data bigger than 20 byte with ble

Victor — Wed, 03 Feb 2016 17:17:20 GMT

Can you please add a reference to the mentioned example? I'm struggling to find a ready solution to data chunking/reassembling.

RE: Sending data bigger than 20 byte with ble

Victor — Wed, 03 Feb 2016 16:17:57 GMT

Can you please elaborate? There are no examples directly in the post, where to look for them? The only ones I found in your Github were for iOS.

RE: Sending data bigger than 20 byte with ble

Ulrich Myhre — Fri, 02 Jan 2015 01:17:20 GMT

You will have to disassemble your data into segments of 20 bytes or less. The data is guaranteed to arrive in the same order it is sent. The receiver will have to store the received data and periodically flush it to e.g. flash memory or a transport like SPI/UART.

There are multiple ways of solving this on both sides. It can be done with notifications alone, or with writes to a characteristic. See the DFU example for some inspiration on how to send larger files like softdevices.

RE: Sending data bigger than 20 byte with ble

Nguyen Hoan Hoang — Tue, 30 Dec 2014 03:00:21 GMT

see examples on this blog site http://embeddedsoftdev.blogspot.ca/p/ehal-nrf51.html