STM32 Real-Time Optimization | TIM/PWM, ADC, DMA, FPU

What we do

We turn your STM32 firmware into hard real-time, low-jitter control code. From TIM/PWM alignment and ADC sampling to DMA pipelines and FPU math, we squeeze deterministic performance out of the clock tree—so your FOC, power stage, or mechatronic loop hits its deadlines every cycle.

Outcomes we target

  • deterministic ISR latency & jitter (µs → sub-µs)

  • glitch-free PWM/ADC synchronization and current sensing

  • DMA-first data paths (double-buffered, zero-copy)

  • safe NVIC priority schemes for RTOS + interrupts

  • predictable FPU/CMSIS-DSP performance (no denorm traps)

  • verified timing budgets with trace logs and acceptance limits

Services

  • Clock Tree & Timing Budget – PLL/HSE setup, bus prescalers, Flash wait-states; end-to-end cycle accounting for your control period.

  • TIM/PWM Engineering – advanced TIM1/TIM8/HRTIM setup; center-aligned PWM, complementary outputs, dead-time comp, BDTR safety, TRGO/trigger chains.

  • ADC Sampling Strategy – injected/regular groups, hardware oversampling, S&H selection, calibration, and sample-at-current-crest alignment to PWM.

  • DMA Pipelines – circular mode, double buffering (DBM), FIFO thresholds, burst sizes; zero-copy paths to control loops and loggers.

  • ISR & NVIC Optimization – tail-chaining aware ISRs, bounded critical sections, preemption groups, configMAX_SYSCALL_INTERRUPT_PRIORITY hygiene.

  • FPU & Math – hard-float ABI, flush-to-zero, fast-math choices, CMSIS-DSP kernels; fixed-point fallbacks where needed.

  • Memory Placement – ITCM/DTCM/CCM SRAM usage for hot code/data; cache maintenance (F7/H7 D-Cache) for DMA safety.

  • Sensing Chain Quality – shunt/OpAmp/DFSDM setup, blanking windows, offset removal, digital filtering with phase awareness.

  • RTOS Integration – ISR-safe drivers, deferred processing, lock-free queues, bounded logging & telemetry.

  • Instrumentation & Test – DWT cycle counter, ITM/SWO/ETM trace, GPIO timestamping, scope/LA scripts, automated timing regression.

Deliverables you receive

  • Timing Budget Report (PDF): target vs. measured cycles, jitter histograms, worst-case paths.

  • Configuration Packs: CubeMX/CubeIDE .ioc, TIM/ADC/DMA init code, NVIC table, linker/memory regions.

  • Patched Drivers & ISRs: HAL/LL or bare-metal variants with comments and guardrails.

  • Trace & Logs: CSV/binary logs, decoded traces, plots; reproducible scripts (Python/MATLAB).

  • Handover Session: 60–90 min live walkthrough + Q&A.

Technical stack

  • MCUs: STM32F3/F4/F7, G4, H7, U5

  • Timers: TIM1/TIM8 (advanced), HRTIM (G4/F3), general-purpose timers, encoder mode

  • ADC: injected/regular, dual simultaneous, oversampling, hardware triggers (TRGO/TRGO2)

  • DMA: DBM, circular, burst, FIFO; mem-to-periph/periph-to-mem; cache coherency on F7/H7

  • Math: FPU single-precision, CMSIS-DSP, fixed-point (Q-formats) where budgets demand

  • Debug: DWT/ITM/ETM, SWO, SEGGER RTT, logic analyzers, oscilloscopes

How an engagement works

  1. Discovery (30 min) – control targets, timing issues, hardware overview.

  2. Profiling & Plan – measure current latencies, propose budgets and changes.

  3. Implementation – TIM/ADC/DMA/ISR/FPU optimizations, memory placement, safety.

  4. Validation – jitter/latency testing across corners (Vbus, temp, load).

  5. Handover – docs, code, acceptance checklist, and team training.

What we need from you

  • MCU model, clock source, current CubeMX/CubeIDE project

  • PWM frequency/topology, current-sense method, ADC channels & timings

  • RTOS (if any), current ISR list with priorities, target control period

  • KPIs: e.g., jitter ≤ 1 µs, loop time ≤ 25% of period, missed deadlines = 0

Packages (example framing—price as you wish)

  • Real-Time Audit – profiling, timing budget, prioritized fix plan.

  • Optimization Sprint  – TIM/ADC/DMA/ISR/FPU changes + validation.

  • Production Hardening – corner-case robustness, cache coherency tests, docs & training.
    (Positioning tip: use “transparent, cost-effective pricing” or a clear price-match policy rather than “cheapest”.)

Example use cases

  • FOC/Drive Control – center-aligned PWM with ADC crest sampling and zero-copy current feedback.

  • Power Electronics – high-frequency HRTIM PWM with deterministic protection paths.

  • Precision Mechatronics – tight position/velocity loops with bounded jitter on RTOS.

  • Sensing & Logging – continuous high-rate acquisition via DMA with zero drops under load.

FAQ

Do you support pure LL/bare-metal without HAL?
Yes—LL or register-level for the hottest paths; HAL where it’s adequate.

Can you fix cache/DMA issues on F7/H7?
We add cache maintenance and/or place DMA buffers in DTCM/AXI SRAM to ensure coherency.

What about FreeRTOS priority inversion?
We design NVIC groups and ISR priorities to keep RTOS APIs safe and latency bounded.

Will this break my MCSDK project?
No—changes are delivered as patches/branches with clear diffs and rollback.