Long write only writes 4 packets

[nejcokle]

Hello,

I'm implementing long write function to my project.

I managed to get it working, but i can't send more than 68 bytes of data. When i'm sending the data, I slice it into <18bytes chunks and send each chunk with correct offset, using "BLE_GATT_OP_PREP_WRITE_REQ" as sending type. When all the data is through i use this command to execute the write: "BLE_GATT_OP_EXEC_WRITE_REQ".

Now no matter how much i send (if it's more than 68 bytes), only 68 bytes come through. When i looked into what comes through i saw that only FIRST 4 packets are recieved, even thought i execute when all packets are sent.

Why are other packets lost?

Best regards, Nejc

[Ulrich Myhre]

Also, it is the sender that will see any errors. When you send a prepare write request, you get a BLE_GATTC_EVT_WRITE_RSP. All the GATTC events have a "gatt_status" flag that contains any error reported by the peer side. In this case, the peer knows that the queue is full, and responds autonomously.

[nejcokle]

Yes, i've seen that table. I made a buffer that's 200 bytes big, and i want to send around 90 - 100 bytes of data, so the buffer should be big enough. Hmm, never thought about that, but i don't really need to write multiple characteristics at once.. Which command do i use then if i just want to update one characteristic, and write in it with offsets? Which parameter should i use instead of "BLE_GATT_OP_PREP_WRITE_REQ"?

Yeah it's really strange there are no errors... I've been working on this problem for a few days now...