.. _bluetooth-ctlr-arch: LE Controller ############# Overview ******** .. image:: img/ctlr_overview.png #. HCI * Host Controller Interface, Bluetooth standard * Provides Zephyr Bluetooth HCI Driver #. HAL * Hardware Abstraction Layer * Vendor Specific, and Zephyr Driver usage #. Ticker * Soft real time radio/resource scheduling #. LL_SW * Software-based Link Layer implementation * States and roles, control procedures, packet controller #. Util * Bare metal memory pool management * Queues of variable count, lockless usage * FIFO of fixed count, lockless usage * Mayfly concept based deferred ISR executions Architecture ************ Execution Overview ================== .. image:: img/ctlr_exec_overview.png Architecture Overview ===================== .. image:: img/ctlr_arch_overview.png Scheduling ********** .. image:: img/ctlr_sched.png Ticker ====== .. image:: img/ctlr_sched_ticker.png Upper Link Layer and Lower Link Layer ===================================== .. image:: img/ctlr_sched_ull_lll.png Scheduling Variants =================== .. image:: img/ctlr_sched_variant.png ULL and LLL Timing ================== .. image:: img/ctlr_sched_ull_lll_timing.png Event Handling ************** .. image:: img/ctlr_sched_event_handling.png Scheduling Closely Spaced Events ================================ .. image:: img/ctlr_sched_msc_close_events.png Aborting Active Event ===================== .. image:: img/ctlr_sched_msc_event_abort.png Cancelling Pending Event ======================== .. image:: img/ctlr_sched_msc_event_cancel.png Pre-emption of Active Event =========================== .. image:: img/ctlr_sched_msc_event_preempt.png Data Flow ********* Transmit Data Flow ================== .. image:: img/ctlr_dataflow_tx.png Receive Data Flow ================= .. image:: img/ctlr_dataflow_rx.png Execution Priorities ******************** .. image:: img/ctlr_exec_prio.png - Event handle (0, 1) < Event preparation (2, 3) < Event/Rx done (4) < Tx request (5) < Role management (6) < Host (7). - LLL is vendor ISR, ULL is Mayfly ISR concept, Host is kernel thread. Lower Link Layer **************** LLL Execution ============= .. image:: img/ctlr_exec_lll.png LLL Resume ---------- .. image:: img/ctlr_exec_lll_resume_top.png .. image:: img/ctlr_exec_lll_resume_bottom.png Bare metal utilities ******************** Memory FIFO and Memory Queue ============================ .. image:: img/ctlr_mfifo_memq.png Mayfly ====== .. image:: img/ctlr_mayfly.png * Mayfly are multi-instance scalable ISR execution contexts * What a Work is to a Thread, Mayfly is to an ISR * List of functions executing in ISRs * Execution priorities map to IRQ priorities * Facilitate cross execution context scheduling * Race-to-idle execution * Lock-less, bare metal Legacy Controller ***************** .. image:: img/ctlr_legacy.png Bluetooth Low Energy Controller - Vendor Specific Details ********************************************************* Hardware Requirements ===================== Nordic Semiconductor -------------------- The Nordic Semiconductor Bluetooth Low Energy Controller implementation requires the following hardware peripherals. .. list-table:: SoC Peripheral Use :header-rows: 1 :widths: 15 15 15 10 50 * - Resource - nRF Peripheral - # instances - Zephyr Driver Accessible - Description * - Clock - NRF_CLOCK - 1 - Yes - * A Low Frequency Clock (LFCLOCK) or sleep clock, for low power consumption between Bluetooth radio events * A High Frequency Clock (HFCLOCK) or active clock, for high precision packet timing and software based transceiver state switching with inter-frame space (tIFS) timing inside Bluetooth radio events * - RTC [a]_ - NRF_RTC0 - 1 - **No** - * Uses 2 capture/compare registers * - Timer - NRF_TIMER0 or NRF_TIMER4 [1]_, and NRF_TIMER1 [0]_ - 2 or 1 [1]_ - **No** - * 2 instances, one each for packet timing and tIFS software switching, respectively * 7 capture/compare registers (3 mandatory, 1 optional for ISR profiling, 4 for single timer tIFS switching) on first instance * 4 capture/compare registers for second instance, if single tIFS timer is not used. * - PPI [b]_ - NRF_PPI - 21 channels (20 [2]_), and 2 channel groups [3]_ - Yes [4]_ - * Used for radio mode switching to achieve tIFS timings, for PA/LNA control * - DPPI [c]_ - NRF_DPPI - 20 channels, and 2 channel groups [3]_ - Yes [4]_ - * Used for radio mode switching to achieve tIFS timings, for PA/LNA control * - SWI [d]_ - NRF_SWI4 and NRF_SWI5, or NRF_SWI2 and NRF_SWI3 [5]_ - 2 - **No** - * 2 instances, for Lower Link Layer and Upper Link Layer Low priority execution context * - Radio - NRF_RADIO - 1 - **No** - * 2.4 GHz radio transceiver with multiple radio standards such as 1 Mbps, 2 Mbps and Coded PHY S2/S8 Long Range Bluetooth Low Energy technology * - RNG [e]_ - NRF_RNG - 1 - Yes - * - ECB [f]_ - NRF_ECB - 1 - **No** - * - CBC-CCM [g]_ - NRF_CCM - 1 - **No** - * - AAR [h]_ - NRF_AAR - 1 - **No** - * - GPIO [i]_ - NRF_GPIO - 2 GPIO pins for PA and LNA, 1 each - Yes - * Additionally, 10 Debug GPIO pins (optional) * - GPIOTE [j]_ - NRF_GPIOTE - 1 - Yes - * Used for PA/LNA * - TEMP [k]_ - NRF_TEMP - 1 - Yes - * For RC sourced LFCLOCK calibration * - UART [l]_ - NRF_UART0 - 1 - Yes - * For HCI interface in Controller only builds * - IPC [m]_ - NRF_IPC [5]_ - 1 - Yes - * For HCI interface in Controller only builds .. [a] Real Time Counter (RTC) .. [b] Programmable Peripheral Interconnect (PPI) .. [c] Distributed Programmable Peripheral Interconnect (DPPI) .. [d] Software Interrupt (SWI) .. [e] Random Number Generator (RNG) .. [f] AES Electronic Codebook Mode Encryption (ECB) .. [g] Cipher Block Chaining (CBC) - Message Authentication Code with Counter Mode encryption (CCM) .. [h] Accelerated Address Resolver (AAR) .. [i] General Purpose Input Output (GPIO) .. [j] GPIO tasks and events (GPIOTE) .. [k] Temperature sensor (TEMP) .. [l] Universal Asynchronous Receiver Transmitter (UART) .. [m] Interprocess Communication peripheral (IPC) .. [0] :kconfig:option:`CONFIG_BT_CTLR_TIFS_HW` ``=n`` .. [1] :kconfig:option:`CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER` ``=y`` .. [2] When not using pre-defined PPI channels .. [3] For software-based tIFS switching .. [4] Drivers that use nRFx interfaces .. [5] For nRF53x Series