STM32 real-time optimization – TIM/PWM, ADC, DMA, FPU

What we do

We turn your STM32 firmware into hard real-time control software with minimal jitter. From precise TIM/PWM alignment and ADC sampling to DMA pipelines and FPU math, we squeeze deterministic performance out of the clock tree so that FOC, power stage or mechatronic control loops hit their deadlines every cycle.

Outcomes we aim for

• Deterministic ISR latency and jitter (microseconds down into sub-µs range).
• Clean PWM / ADC synchronisation and reliable current measurement.
• DMA-first data paths with double buffering and zero-copy into control loops.
• Safe NVIC priority schemes that keep RTOS and interrupts working together.
• Predictable FPU / CMSIS-DSP performance without denorm traps.
• Verified timing budgets with trace logs and clear acceptance criteria.

Services

• Clock tree and timing budget – PLL / HSE setup, bus prescalers, flash wait states and end-to-end cycle accounting for your control period.
• TIM / PWM engineering – advanced TIM1 / TIM8 / HRTIM setup, centre-aligned PWM, complementary outputs, dead-time compensation, BDTR safety features and TRGO trigger chains.
• ADC sampling strategy – injected vs. regular groups, hardware oversampling, S&H configuration, calibration and sampling at current peaks aligned to PWM.
• DMA pipelines – circular mode, double buffering (DBM), FIFO thresholds and burst sizes; zero-copy paths into controllers and loggers.
• ISR and NVIC optimisation – tail-chaining-aware ISRs, bounded critical sections, preemption groups and clean configMAX_SYSCALL_INTERRUPT_PRIORITY practice.
• FPU and math – hard-float ABI, flush-to-zero, fast-math options, CMSIS-DSP kernels and fixed-point fallbacks where budgets demand it.
• Memory placement – ITCM / DTCM / CCM-SRAM for hot code and data, cache maintenance for F7 / H7 to keep DMA safe and coherent.
• Measurement chain quality – Shunt / OpAmp / DFSDM setup, blanking windows, offset removal and digital filtering with phase awareness.
• RTOS integration – ISR-safe drivers, deferred processing, lock-free queues and bounded logging / telemetry overhead.
• Instrumentation and test – DWT cycle counters, ITM / SWO / ETM trace, GPIO time stamps, scope / logic-analyser scripts and automated timing regression.

Your deliverables

• Timing-budget report (PDF) with target vs. measured cycles, jitter histograms and worst-case paths.
• Configuration package: CubeMX / CubeIDE .ioc, TIM / ADC / DMA init code, NVIC table and linker / memory regions.
• Patched drivers and ISRs (HAL / LL or bare-metal) with comments and guardrails for future changes.
• Traces and logs: CSV / binary logs, decoded traces, plots and reproducible analysis scripts (Python / MATLAB).
• Handover session (60–90 minutes) with live walkthrough and Q&A for your team.

Technology stack

• MCUs: STM32F3 / F4 / F7, G4, H7, U5.
• Timers: TIM1 / TIM8 (advanced), HRTIM (G4 / F3), general-purpose timers and encoder modes.
• ADC: injected and regular groups, dual simultaneous modes, oversampling and hardware triggers (TRGO / TRGO2).
• DMA: double-buffer (DBM), circular, burst, FIFO, mem⇄periph transfers and cache coherence on F7 / H7.
• Math: single-precision FPU, CMSIS-DSP and fixed-point (Q-formats) where timing or determinism requires it.
• Debug: DWT / ITM / ETM, SWO, SEGGER RTT, logic analysers and oscilloscopes.

Engagement flow

• Discovery (30 minutes) – control goals, timing issues and hardware overview.
• Profiling and plan – measure current latencies, define budgets and propose concrete changes.
• Implementation – TIM / ADC / DMA / ISR / FPU optimisations, memory placement and safety checks.
• Validation – jitter and latency tests across corners (DC-bus, temperature, load).
• Handover – documentation, code, acceptance checklist and team training.

What we need from you

• MCU type, clock source and the current CubeMX / CubeIDE project.
• PWM frequency and topology, current-measurement method and ADC channels / timings.
• RTOS details (if any), current ISR list with priorities and target control period.
• KPIs such as jitter ≤ 1 µs, loop execution time ≤ 25 % of the period and zero missed deadlines.

Example packages

• Real-time audit – profiling, timing budget and a prioritised fix list.
• Optimization sprint – TIM / ADC / DMA / ISR / FPU changes plus validation.
• Production hardening – corner robustness, cache-coherence tests, documentation and training.

Example use cases

• FOC and drive control – centre-aligned PWM with peak-current sampling and zero-copy current feedback.
• Power electronics – high-frequency HRTIM PWM with deterministic protection paths.
• Precision mechatronics – tight position and speed control with bounded jitter under RTOS.
• Measurement and logging – continuous high-rate acquisition via DMA without data drops under load.

FAQ