2017-07-05 04:27 PM
The BlueNRG-MS library for BLE v4.1 sets ATT_MTU to 23 bytes. Is it possible to increase this limit as long as it's less than the 255 character value length limit?
I am working with the SensorTile eval board with an STM32L4xx MCU, and I working with a modified version of the BlueMicrosystem2 example.
I've done the following:
Am I missing anything? Or is it not possible to increase the ATT_MTU?
#bluenrg-ms #stm32l4 #sensor-tile #bleSolved! Go to Solution.
2017-08-22 06:38 PM
There's nothing you can do to increase ATT_MTU over 20 bytes for BlueNRG-MS, you'd have to upgrade your bluetooth module to something that supports an ATT_MTU of more than 20 bytes.
My team upgraded to BlueNRG-2, which can give us an ATT_MTU of up to 158 bytes according to the datasheet.
2017-08-05 02:26 AM
Hi,
I also facing the same problem. please help some one to solve this issue.
2017-08-05 11:25 PM
After getting in touch with an ST representative, I've verified that it is not possible to increase the ATT_MTU of the BlueNRG-MS module.
2017-08-22 03:00 AM
Hi Mick,
Thanks for the reply.
Our application required to transfer 60bytes per packet. is there any way to transfer more than 20bytes per packet using BlueNRG-MS module to android device?
2017-08-22 06:38 PM
There's nothing you can do to increase ATT_MTU over 20 bytes for BlueNRG-MS, you'd have to upgrade your bluetooth module to something that supports an ATT_MTU of more than 20 bytes.
My team upgraded to BlueNRG-2, which can give us an ATT_MTU of up to 158 bytes according to the datasheet.
2018-02-11 06:09 PM
Hi Mick,
I'm having this same problem and trying to verify whether the 20byte limit is mentioned somewhere in documentation. Can you point me to the correct documentation location.
I have a 93 byte characteristic. If I trigger a read from the central side I get the full 93 bytes at the central. But if I try to push as an update from peripheral side I only get 20 bytes at the central. The problem seems to occur only when sending data as updates.
Regards,
Asela.
2018-02-12 04:35 PM
Got further information about documentation, in this thread.
https://community.st.com/0D50X00009XkWi6SAF
/Asela
2023-08-28 04:03 AM
hi .
I am using bluenrg-2a1 module with nuclel476rg .
Problem 1:
while sending the data from central to peripheral , i am always rx 20 bytes only but central and peripheral has accepted for 220bytes exchange at the time of mtu exchange.
problem 2:
from peripheral to central i am sending 200bytes of data but i am able to rx only 183 bytes of data
Note:
mtu exchange acceptance value between central and peripheral is 220bytes of data.
ble stack init with the max mtu size as 220.
i have tried in many ways , but i was not able to fix it. if anyone knows it how to fix it/ any document related to this , kindly revert back asap.
2024-07-11 08:26 AM
Hallo,
in BLUENRG-2, how to increase ATT_MTU to more than 158 bytes?to the maximum (247)?
Thank you.