Forums - About the change for Max PDU size as 251Bytes for QCA4024

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About the change for Max PDU size as 251Bytes for QCA4024
bolo.tsai
Join Date: 19 Jul 18
Posts: 20
Posted: Wed, 2018-10-24 00:53
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Dear Sirs,

I have tried to set the max PDU size (max packet size of Link Layer) as 251 Bytes (the default 27 Bytes provided at the SDK) but it is failed to change. The max PDU size seems to be limited to 81 bytes by BLE firmwre as the setting for the value above this bound would get the failure message. I have checked the DLE (Data Length Extension) has been enabled at the HCI supported features when link is connected. So is there any way to change the max PDU size as 251 bytes ? Thanks.

Best Regards,

Bolo

 

 

 

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Re: About the change for Max PDU size as 251Bytes for QCA4024
jaydenk
Join Date: 21 Jun 18
Posts: 64
Posted: Wed, 2018-10-24 21:30
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HI bolo.tsai,

Could you let me know which API are you using for 251 bytes?

Thanks
BR,
Jayden

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Re: About the change for Max PDU size as 251Bytes for QCA4024
bolo.tsai
Join Date: 19 Jul 18
Posts: 20
Posted: Wed, 2018-10-24 22:43
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Hi Jayden,

I use qapi_BLE_HCI_Host_Buffer_Size to set the max PDU size but it would get 16 returned at StatusResult. Is there other way to change the max PDU size as 251-bytes ? Thanks.

Regards,

Bolo

 

 

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Re: About the change for Max PDU size as 251Bytes for QCA4024
jaydenk
Join Date: 21 Jun 18
Posts: 64
Posted: Thu, 2018-10-25 14:31
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Hi Bolo,

For BLE Data Length Extension, can you try to use qapi_BLE_GAP_LE_Set_Data_Length()?

QCLI Demo also exposes a command "SetDataLength" corresponding the QAPI.

Thanks
BR,
Jayden

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Re: About the change for Max PDU size as 251Bytes for QCA4024
bolo.tsai
Join Date: 19 Jul 18
Posts: 20
Posted: Mon, 2018-10-29 00:45
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Hi Jayden,

I have tried to use SetDataLength command to set 251 (i.e. max TX PDU 251 bytes)  but no messages shown at QAPI_BLE_ET_LE_DATA_LENGTH_CHANGE_E of GAP_LE_Event_Callback. When I set 81 by using SetDataLength, the data length exchange messages can be seen at the console (the messages listed at QAPI_BLE_ET_LE_DATA_LENGTH_CHANGE_E of GAP_LE_Event_Callback). Below is the execution logs captured from the console and FYI. Can you tell me how to  successfully set 251B tx pdu size ? Thanks

 

E> setdatalength 251
BLE: SetDataLength: Suggest Tx Packet Size     : 251.
BLE: SetDataLength: Suggest Tx Packet Time (us): 2120.
BLE> setdatalength 69
BLE: SetDataLength: Suggest Tx Packet Size     : 69.
BLE: SetDataLength: Suggest Tx Packet Time (us): 664.
BLE: etLE_Data_Length_Change with size 14.
BLE:   Connection Address:                 0x516C0E9B5766.
BLE:   Max Tx Octets:                      69.
BLE:   Max Tx Time:                        664.
BLE:   Max Rx Octets:                      81.
BLE:   Max Rx Time:                        760.
BLE>
BLE: etHCI_Connection_Complete with size 20.
BLE:    Status:                0.
BLE:    Connection Handle:     69.
BLE:    Role:                  Slave.
BLE:    Peer Address Type:     QAPI_BLE_LAT_PUBLIC_IDENTITY_E.
BLE:    Peer Address:          0x000002F80051.
BLE:    Connection  Interval:  8.
BLE:    Connection  Latency:   0.
BLE:    Supervision Timeout:   1550.
BLE:    Master Clock Accuracy: 1.
 

Best Regards,

Bolo

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Re: About the change for Max PDU size as 251Bytes for QCA4024
jaydenk
Join Date: 21 Jun 18
Posts: 64
Posted: Mon, 2018-10-29 13:48
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Hi Bolo,

Thanks for your trial.
Maximum BLE Data Payload is configured via NVM.
If we increase the size, we need to increase the value to 255 (0xFF) in NVM.
Default value was 81 (0x51).

With following change in NVM, you can increase BLE Data Size up to 251 by qapi_BLE_GAP_LE_Set_Data_Length().

@QCA4020_2p0.nvm
[Tag0]
TagNum = 1
TagLength = 13
- TagValue = 51 00 72 06 04 10 10 14 14 10 04 FB 00
+ TagValue = FF 00 72 06 04 10 10 14 14 10 04 FB 00

Please refer section 3.6.1.1 BLE size parameters in 80-YA121-142 QCA402x (CDB2x) Programmers Guide.

Thanks
BR,
Jayden

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Re: About the change for Max PDU size as 251Bytes for QCA4024
bolo.tsai
Join Date: 19 Jul 18
Posts: 20
Posted: Tue, 2018-11-06 19:07
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Hi Jayden,

I would try it and thanks for your so helpful information.

BR,

Bolo

 

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Re: About the change for Max PDU size as 251Bytes for QCA4024
bolo.tsai
Join Date: 19 Jul 18
Posts: 20
Posted: Tue, 2018-11-06 19:48
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Hi Jayden,

I can successfully change the BLE Data Size to max 251B according to your suggestion at the last reply. I am very appreciated your help.

BR,

Bolo

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