How to increase the MTU size in NRF52833?

RE: How to increase the MTU size in NRF52833?

lara — Thu, 19 Dec 2024 12:05:25 GMT

yes simon it works for both nrf52833 and 52840 dongle aswell.it helped me like a heaven..haha..Thank you for ur kind response.

RE: How to increase the MTU size in NRF52833?

Simonr — Tue, 17 Dec 2024 15:31:07 GMT

What was the change necessary to achieve the MTU size you required? THe nRF52840 Dongle should work as long as you set the correct board file for it. The configs should work the same.

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Tue, 17 Dec 2024 05:53:37 GMT

Connected
MTU exchange successfulNew MTU: 244 bytes

..........now its changed to 244 bytes,thank you simon for the kind support...

can i use the same config with nrf52840 dongle?

RE: How to increase the MTU size in NRF52833?

Simonr — Mon, 16 Dec 2024 15:18:25 GMT

Are you able to upload the verbose/debug log from the phone here so we can review it?

Did you try increasing some of the stack sizes in your configs on your end? Specifically the ones below:

CONFIG_BT_RX_STACK_SIZE=1024

CONFIG_BT_HCI_TX_STACK_SIZE_WITH_PROMPT=y

CONFIG_BT_HCI_TX_STACK_SIZE=640

CONFIG_MAIN_STACK_SIZE=1024

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Mon, 16 Dec 2024 09:42:24 GMT

i tried in 3 different phones but it still the same size

RE: How to increase the MTU size in NRF52833?

Simonr — Thu, 12 Dec 2024 14:58:44 GMT

Try pressing the INFO tab on your phone and set it to VERBOSE or DEBUG to get more logging information, as the INFO only provides the most basic of information.

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Thu, 12 Dec 2024 07:24:19 GMT

iam using android phone,realme 5 pro.giving input through nrf connect app

RE: How to increase the MTU size in NRF52833?

Simonr — Mon, 09 Dec 2024 15:21:59 GMT

What phone is this exactly, an iOS device or Android device, and which model? You should be able to see some logging in the nRF Connect app for mobile as well (by swiping right on Android for example). Do you see any information about the MTU exchange on the phone side of things?

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Mon, 09 Dec 2024 13:51:16 GMT

iam using NRF52833DK,enabled GATT. my central device is mobile phone.in nrf connect app,iam connecting with nrf52833 and giving the input.it receives the input only less than 62 bytes

RE: How to increase the MTU size in NRF52833?

Simonr — Mon, 09 Dec 2024 13:00:03 GMT

What is the device you're connecting to here. I don't think this is directly related to the RAM and Flash memory allocated to your device, but rather the connection being the restricting factor of the MTU size that's being set. Are you connecting to a phone, another nRF52 series DK or a computer here? It will always be the central device that has the final say in an MTU exchange, and if it doesn't agree or support with the suggested MTU size from the peripheral, it can always lower this to whatever it supports. So please share some details on the device you're connecting to.

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Sat, 07 Dec 2024 06:25:06 GMT

can you brief the steps to increase the ram and flash size in nrf52833?

RE: How to increase the MTU size in NRF52833?

lara — Sat, 07 Dec 2024 06:23:25 GMT

i got this output when trying to increase MTU size: "MTU exchange successfulNew MTU: 62 bytes"

i dont get any kind of error code,

still i cannot able to increase the Flash and RAM memory ,will this impact on increasing mtu size?

RE: How to increase the MTU size in NRF52833?

Simonr — Fri, 06 Dec 2024 12:21:28 GMT

Yes, increasing the app Flash and RAM primary address ranges should be the way to make these ranges longer. More info in the memory layout configs documentation. After you've done so, what seems to be the limiting factor when trying to increase the MTU size on your end? What happens when running the application here? Enabling debugging and logging should give you some sort of error code when trying to set the MTU size any higher.

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Thu, 05 Dec 2024 11:23:11 GMT

understood..prj_minimal.conf contains...

CONFIG_BT_RX_STACK_SIZE=1024
CONFIG_BT_HCI_TX_STACK_SIZE_WITH_PROMPT=y
CONFIG_BT_HCI_TX_STACK_SIZE=640
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=1536
CONFIG_MPSL_WORK_STACK_SIZE=640
CONFIG_MAIN_STACK_SIZE=1024
CONFIG_IDLE_STACK_SIZE=128
CONFIG_ISR_STACK_SIZE=1024

# Disable features not needed
CONFIG_TIMESLICING=n
CONFIG_COMMON_LIBC_MALLOC=n
CONFIG_LOG=n
CONFIG_ASSERT=n

# Disable Bluetooth features not needed
CONFIG_BT_DEBUG_NONE=y
CONFIG_BT_ASSERT=n
CONFIG_BT_DATA_LEN_UPDATE=n
CONFIG_BT_PHY_UPDATE=n
CONFIG_BT_GATT_CACHING=n
CONFIG_BT_GATT_SERVICE_CHANGED=n
CONFIG_BT_GAP_PERIPHERAL_PREF_PARAMS=n
CONFIG_BT_SETTINGS_CCC_LAZY_LOADING=y
CONFIG_BT_HCI_VS=n

# Disable Bluetooth controller features not needed
CONFIG_BT_CTLR_PRIVACY=n
CONFIG_BT_CTLR_PHY_2M=n

# Reduce Bluetooth buffers
CONFIG_BT_BUF_EVT_DISCARDABLE_COUNT=1
CONFIG_BT_BUF_EVT_DISCARDABLE_SIZE=43
CONFIG_BT_BUF_EVT_RX_COUNT=2

CONFIG_BT_CONN_TX_MAX=3
CONFIG_BT_L2CAP_TX_BUF_COUNT=2
CONFIG_BT_ATT_TX_COUNT=2
CONFIG_BT_BUF_ACL_TX_COUNT=3
CONFIG_BT_BUF_ACL_TX_SIZE=27

partitions.yml

app:
address: 0x0
end_address: 0x3e000
region: flash_primary
size: 0x3e000
settings_storage:
address: 0x3e000
end_address: 0x40000
placement:
    align:
      start: 0x1000
    before:
    - end
region: flash_primary
size: 0x2000
sram_primary:
address: 0x20000000
end_address: 0x20008000
region: sram_primary
size: 0x8000

can you little elaborate on this?

also i couldnot exceed mtu payload size more than 62 bytes..

RE: How to increase the MTU size in NRF52833?

Simonr — Thu, 05 Dec 2024 08:00:40 GMT

This is because the nRF Connect SDK sets region sizes for your application that aren't necessarily using the full flash/RAM of your devices. Have you for example enabled debugging in your configs, or are you using MCUBoot? You can check out the Memory footprint optimization documentation available here to see how to change these region sizes.

Best regards,

Simon

RE: How to increase the MTU size in NRF52833?

lara — Wed, 04 Dec 2024 12:49:15 GMT

Memory region         Used Size Region Size %age Used
           FLASH:      203344 B       248 KB     80.07%
             RAM:       29188 B        32 KB     89.07%
        IDT_LIST:          0 GB        32 KB      0.00%

Build Board target: NordiC Kits.

according to datasheet..512 KB Flash + 128 KB RAM for NRF52833DK.but the build log showing only 32kB of RAM,248kB of Flash???

i cannot extend the payload size more than 62 bytes.

also when i used this below config iam facing ram is overflowing error.

i only used CONFIG_BT_USER_DATA_LEN_UPDATE=Y in proj.conf,then mtu size extend to 62 bytes.but i need to extend it upto 247 bytes atleast.

CONFIG_BT_USER_DATA_LEN_UPDATE=y
CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
CONFIG_BT_BUF_ACL_RX_SIZE=251
CONFIG_BT_BUF_ACL_TX_SIZE=251
CONFIG_BT_L2CAP_TX_MTU=247

RE: How to increase the MTU size in NRF52833?

lara — Wed, 04 Dec 2024 09:43:47 GMT

Thank you for the quick reply,i dont know how i missed the lesson.

RE: How to increase the MTU size in NRF52833?

Simonr — Wed, 04 Dec 2024 08:20:28 GMT

Please check out our Bluetooth LE fundamentals course in DevAcademy here where data length and MTU is explained in the Connection parameters section of Lesson 3. You can also use Lesson 3, exercise 2 for reference of increasing your data length and MTU size. https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/lessons/lesson-3-bluetooth-le-connections/topic/blefund-lesson-3-exercise-2/

Best regards,

Simon