• State Not Answered
  • Replies 49 replies
  • Subscribers 26 subscribers
  • Views 3827 views
  • Users 0 members are here
Attachments (2) Download All
Nordic Case Info
  • Case ID: 267225
Options

BLE lost messages

user93218

Hi, as part of my project i have 2 nordic 52dks one as a pheripheral (sending) and on as a client (recieving). where i am sening a buffer of 8, in the order

buffer[0] = 10

buffer[1}= X gyro lsb

buffer[2] = X gyro msb

buffer[3] = y gyro lsb

buffer[4] = y gyro msb

buffer[5] = z gyro lsb

buffer[6] = z gyro msb

buffer[7] = 36   //terminator $

however sometimes i seem to lose a byte over ble such that the next byte received will be less and hence the order is correupted thus making processing rather and unpredictable for a large sample size like 1000000 samples.

how may i ensure that my ble settings are correct such that i ensure to limit this issue.

my code was based of the examples ble_app_uart and ble_app_uart_c for the peripheral and client respectivly.

thank u in advance 

  • 0 in reply to user93218
    NikolaiDimech98 said:
    im not sure if wat im saying is understandable.

    I think I get the picture, but thank you for the understanding.

    NikolaiDimech98 said:
    umm.. im not really sure is there a max value ?

    I dont think there is a max value other than the physical limitations of the SoC - i.e how much RAM do you have to spare?
    However, allocating everything that you have spare is not the best approach for this. Rather, you should look at how much that will actually be transferred in each interval.
    For example, how much throughput do you need to have all the necessary sensor data sent each second, and how much latency can you have in your system?
    If you group multiple measurements together up till the MTU size, and increase the connection event lengths, you will be able to send multiple larger packets per connection interval, for instance.
    But, in order to determine what configuration you should use, you need to know more exactly how many bytes you intend to transfer, and how often you intend to transfer them.
    You could take a look at the BLE throughput tables in the SoftDevice docuementation to determine the best connection parameters and configuration for your application.

    It could also be helpful for you to check out the the Online Power Profiler to visualize how each transfer will happen, with the different connection configurations.

    Please do not hesitate to ask if any part of my answer should be unclear!

    Best regards,
    Karl

  • 0 in reply to user87869

    ok so let say i want to have this configuration 

    is it possible to be shown how or what i would need to change. also as previously mentioned i would like to remove the delay such that i make it interrupt based and use the BLE_GATTS_EVT_HVN_TX_COMPLETE event which should ensure no resetting of the mcu .

    i would like to transfer a max of 242 bytes at once if possible with an output data rate of max 400 (the sesnor supports a data rate of 2000) but this setting should be enough for my application which setting do you suggest and the connection between the pheripheral and client is always active such that if theres data is constantly sent at the set settings

  • 0 in reply to user93218

    but anything i change results in the central not connecting so i am very confused at what is going on and ideally i would like to have the configuration of the fastest transfer

Related
Terms of service