I am currently working on a project involving the Nordic nRF52840-DK development boards (1 Central and 11 Peripherals communication), with LE PHY Coded S8. In this project, I have encountered challenges related to the connection interval and packet transmission, and I am seeking your guidance to resolve these issues.
- Connection Event:
- In some occurrences the observed packet duration is over 12 ms.
- The current connection event is set to 10 ms.
CONFIG_BT_CTLR_SDC_MAX_CONN_EVENT_LEN_DEFAULT=10000
Connection Interval is 60ms. - Based on calculations, if the packet duration is 12 ms and all eleven Peripherals are exchanging packets with the Central, the total duration would be 132 ms, which exceeds the interval for a single connection event.
In this regard, I request your assistance to clarify the following aspects: a. What factors could contribute to the observed packets duration exceeding the desired connection event? Which Zephyr configuration options should I modify to achieve optimal connection event length in this specific use case?
2. Optimizing Packet Transmission:
- I have already reviewed the payload size and data rate in my code to optimize packet transmission efficiency.
- However, I would appreciate your guidance on the following aspects related to Zephyr and the Nordic nRF52840-DK boards: a. Are there any specific BLE parameters or Zephyr configuration options that can be adjusted to optimize packet transmission further? b. What are the recommended settings and values for these parameters to achieve efficient packet transmission in this context?
To provide more context, here are the relevant details of my configuration and environment:
- Nordic nRF52840-DK development boards with LE PHY Coded S=8.
- Central Specific Config:
CONFIG_BT_MAX_CONN=12CONFIG_BT_CTLR_SDC_MAX_CONN_EVENT_LEN_DEFAULT=10000CONFIG_BT_L2CAP_TX_MTU=255CONFIG_BT_BUF_ACL_TX_SIZE=83CONFIG_BT_BUF_ACL_RX_SIZE=83CONFIG_BT_CTLR_DATA_LENGTH_MAX=39CONFIG_BT_CONN_TX_MAX=100
