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S132 v3 Exchange MTU (LE Data Packet Length Extension does't work)

eyeye

Hi, I encountered some problem using the S132v3.

With the s132 v3 and sdk12, I want to extend the ble transfer size.

Now I can change the att_mtu to 100, and iphone can write more than 20bytes to the characteristic.

But!!! I found that the LL Data PDU is fragmented by 27bytes, so the pdu length is still not extended.

When I dig deeper with the sniffer, I found that nRF52 response the LL_LENGTH_REQ cmd with LL_UNKNOWN_RSP. It should be LL_LENGTH_RSP with a BLE_EVT_DATA_LENGTH_CHANGED event to the app layer.

I also use sd_ble_opt_set(BLE_GAP_OPT_EXT_LEN, &option), but no effect.

There must be something wrong with the S132 or me... I need you help or a S132 bugfix.

image description

After using the examples from Petter Myhre

GATT Client: nRF52 DK GATT Server: nRF52 DK LL_LENGTH_REQ ---- LL_LENGTH_RSP image description

GATT Client: iPhone6 iOS10 GATT Server: nRF52 DK LL_LENGTH_REQ ---- LL_UNKNOWN_RSP image description

Both the LL_LENGTH_REQ packet are the same, but the s132 doesn't response to iphone.

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    @eyeye sniffer traces you've posted show that iPhone 6 doesn't support DLE as it responds LL_UNKNOWN_RSP to nordic's LL_LENGTH_REQ. Note that GATT server/client is a different concept from central/peripheral denoted on sniffer traces master/slave. Most notably GATT server - the nRF is a slave device on sniffer.

    So not a bug in S132, maybe a bug in iPhone if Apple intended to support DLE. Also I've done some reading around and as far as user testimonials go Nexus 5x is the only device I could find confirmation of DLE.

    I also found this article: www.argenox.com/.../ denying iPhone support for DLE.

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    @eyeye sniffer traces you've posted show that iPhone 6 doesn't support DLE as it responds LL_UNKNOWN_RSP to nordic's LL_LENGTH_REQ. Note that GATT server/client is a different concept from central/peripheral denoted on sniffer traces master/slave. Most notably GATT server - the nRF is a slave device on sniffer.

    So not a bug in S132, maybe a bug in iPhone if Apple intended to support DLE. Also I've done some reading around and as far as user testimonials go Nexus 5x is the only device I could find confirmation of DLE.

    I also found this article: www.argenox.com/.../ denying iPhone support for DLE.

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