CC2541: Notification Data more than 20 Bytes

Abhishek Sharma3

Prodigy 85 points

Part Number: CC2541

Hi,

I it possible to send more than 20 bytes of data over notification using BLE Stack BLE-CC254x-1.4.2.2.

As when i am send 20 Bytes it is working properly but when i am sending 21 bytes data is not coming.

#define SIMPLEPROFILE_CHAR4_LEN 21

VOID memcpy( (void *)arr_rx_uart, "Abhishek Sharmakumar1", SIMPLEPROFILE_CHAR4_LEN );

SimpleProfile_SetParameter( SIMPLEPROFILE_CHAR4, SIMPLEPROFILE_CHAR4_LEN, (void *)arr_rx_uart);

it is working when i am setting #define SIMPLEPROFILE_CHAR4_LEN 20

over 6 years ago

0 J Lindh over 6 years ago

TI__Guru 57865 points

Hey,
Even though the max length of an attribute value is logically 512 bytes, the Maximum Transmission Unit (MTU) size for ATT can be lower - minimum 27 bytes, not accounting for L2CAP and ATT command header. If the ATT value length exceeds the MTU size, the data will need to be split into smaller parts before being sent. This is done by performing a GATT ReadLongCharValue or GATT WriteLongCharValue procedure..

0 Abhishek Sharma3 over 6 years ago in reply to J Lindh

Prodigy 85 points

Thanks Joakim for clarification.

Bluetooth®︎

Bluetooth forum

CC2541: Notification Data more than 20 Bytes