Is there a max size for device information?

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cross mob
Anonymous
Not applicable

If we wanted to use the Device Information Manufacturing String characteristic is there a max size that this string can be?

I see the BLEPROFILE_DB_PDU has a length field, a header field and a pdu field as LEATT_ATT_MTU-1 ...

So, this amounts to 24 bytes. Even though I thought it was 25 bytes.

So, if one needs to send a string larger than this packet size is it OK to do ?

For example, is there a max size for a variable string in any characteristic?

Thanks


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VictorZ_46
Employee
Employee
5 comments on blog 25 sign-ins 250 likes received

if you check the definition for BLEPROFILE_DB_PDU in the bleprofile.h file, the max pdu is LEATT_ATT_MTU-1, and LEATT_ATT_MTU is 23.  The characteristic value that application can read and write to the database can be 22 octets in length.  Meanwhile for the GATT Write to fit into a single packet the size of the information should be ATT_MTU-3.  So I would recommend to stick to 20 octets max.

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VictorZ_46
Employee
Employee
5 comments on blog 25 sign-ins 250 likes received

if you check the definition for BLEPROFILE_DB_PDU in the bleprofile.h file, the max pdu is LEATT_ATT_MTU-1, and LEATT_ATT_MTU is 23.  The characteristic value that application can read and write to the database can be 22 octets in length.  Meanwhile for the GATT Write to fit into a single packet the size of the information should be ATT_MTU-3.  So I would recommend to stick to 20 octets max.

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