Result of bt_nus_get_mtu() is too small

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Sat, 08 Jul 2023 01:17:23 GMT

Thanks for your reply!

RE: Result of bt_nus_get_mtu() is too small

Naeem Maroof — Fri, 07 Jul 2023 16:32:09 GMT

Hello,

It would purely depend upon your application and needs

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Wed, 05 Jul 2023 01:30:24 GMT

Do you have suggested value of MTU?

RE: Result of bt_nus_get_mtu() is too small

Naeem Maroof — Tue, 04 Jul 2023 17:56:45 GMT

[quote user="snowuyl"]_gBtNusMtu=244[/quote]

Is that not what you wanted to get?

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Mon, 03 Jul 2023 09:51:48 GMT

Thanks for your reply! I have added more configuration in prj.conf to fix this issue.

CONFIG_BT_BUF_ACL_RX_SIZE=251
CONFIG_BT_ATT_PREPARE_COUNT=2
CONFIG_BT_L2CAP_TX_MTU=247
CONFIG_BT_BUF_ACL_TX_COUNT=10
CONFIG_BT_BUF_ACL_TX_SIZE=251
CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
CONFIG_BT_CTLR_RX_BUFFERS=2

Log message is as follows.

_gBtNusMtu=244

RE: Result of bt_nus_get_mtu() is too small

Naeem Maroof — Mon, 03 Jul 2023 09:22:05 GMT

The project you have send is not compiling

As you have provided no other information except the zip file, I opened the project in VS Code and built with NCS 2.3.0 for the 52840DK; it produced so many errors.

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Wed, 28 Jun 2023 05:38:49 GMT

You can see prj.conf after you unzipped minimal_log_nus.zip file.

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Wed, 28 Jun 2023 05:37:12 GMT

devzone.nordicsemi.com/.../5684.minimal_5F00_log_5F00_nus.zip

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Wed, 28 Jun 2023 05:36:28 GMT

devzone.nordicsemi.com/.../2084.custom_5F00_nrf52832.zip

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Wed, 28 Jun 2023 04:03:42 GMT

Thanks for your reply! I have set CONFIG_BT_L2CAP_TX_MTU=128 in prj.conf. But result of bt_nus_get_mtu() is still 20.

The following are log messages of RTT.

# SEGGER J-Link RTT Viewer V6.32i Terminal Log File
# Compiled: 15:22:50 on Jul 24 2018
# Logging started @ 28 Jun 2023 13:29:48
0> *** Booting Zephyr OS build v3.2.99-ncs2 ***
0> btInit() e
0> bt_passkey_set(123456)
0> _btReady(0) e
0> Bluetooth initialized
0> _btReady(0) x
0> btInit() x
0> button pressed
0> power up
0> connected() e
0> Connected 48:41:0F:B4:93:23 (random)
0> _gCurrentConn=0x20001e38
0> bt_nus_get_mtu(0x20001e38)=20

RE: Result of bt_nus_get_mtu() is too small

Naeem Maroof — Fri, 16 Jun 2023 11:00:10 GMT

Hello,

Thank you for contacting DevZone at NordicSemi.

Please have a look at kconfig CONFIG_BT_L2CAP_TX_MTU to set mtu size.

You would like to meet the dependencies of the option.

At the end after compiling, it is good idea to check values of configurations in the /build/zephyr/.config file for confirmation.

Regards,

Naeem

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Thu, 15 Jun 2023 08:45:24 GMT

devzone.nordicsemi.com/.../1586.minimal_5F00_log_5F00_nus.zip

RE: Result of bt_nus_get_mtu() is too small

snowuyl — Thu, 15 Jun 2023 08:45:04 GMT

devzone.nordicsemi.com/.../3362.custom_5F00_nrf52832.zip