STMicroelectronics STM32F042K6U6

Overview

STM32F042K6U6 from STMicroelectronics is an ARM® Cortex®-M0 32-bit microcontroller with 32 KB Flash, 6 KB SRAM, crystal-less USB 2.0 Full-Speed interface, CAN 2.0B controller, and integrated 12-bit ADC (1.0 µs conversion). It operates from 2.0–3.6 V, supports up to 48 MHz CPU frequency, and integrates RTC with alarm and periodic wakeup-enabling compact, cost-sensitive industrial sensor nodes and USB-connected control peripherals.

For engineers reviewing the STM32F042K6U6 datasheet, STM32F042K6U6 pinout, STM32F042K6U6 application, or STM32F042K6U6 equivalent, key selection considerations include USB FS timing autonomy (48 MHz internal oscillator with automatic trimming), CAN+USB coexistence in a single 48-pin UFQFPN package, 5 V-tolerant I/O capability on 24 pins, and hardware CRC for firmware integrity verification in resource-constrained embedded systems.

Technical Context

The STM32F042K6U6 implements a tightly integrated mixed-signal MCU architecture: its clock system combines a 48 MHz internal HSI48 oscillator (with USB-specific auto-trimming against external sync) and dual crystal oscillators (4–32 MHz HSE + 32 kHz LSE), enabling precise USB frame timing without external crystal. The device integrates dedicated peripheral interconnects-including DMA channels routed to ADC, timers, and communication interfaces-to support deterministic real-time data acquisition and protocol handling.

Its power architecture includes independent analog supply (VDDA), programmable voltage detector (PVD), and three low-power modes (Sleep/Stop/Standby) with RTC and backup register retention via VBAT. The 12-bit ADC features separate analog reference (2.4–3.6 V range), hardware oversampling, and direct DMA coupling-optimized for sensor signal conditioning in battery-backed applications.

Key Specifications

Pinout & Package

STM32F042K6U6 is housed in a 48-pin Ultra-Fine Pitch Quad Flat No-lead (UFQFPN48) package with 0.5 mm pitch, 7 × 7 mm body, and exposed thermal pad. Pin assignments follow ST's standard STM32F042x6 pinout for UFQFPN48, validated per datasheet Section 4 (Pinouts and pin descriptions) and Table 13 (STM32F042x pin definitions).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller applications.

Compared with STM32F072CBT6, the STM32F042K6U6 trades Flash/SRAM capacity for lower cost and crystal-less USB; compared with STM32G031K8U6, it retains CAN at the expense of modern security features-making it optimal for established industrial protocols where CAN+USB coexistence is non-negotiable.

Availability

STM32F042K6U6 is available at Aetrix Electronics and suitable for industrial sensor nodes, USB human interface devices, automotive body control subsystems, and CAN-USB bridge adapters requiring stable component supply across multi-year production cycles.

Supply support for STM32F042K6U6 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog products for industrial, automotive, and consumer markets.

The STM32F0 series targets cost-sensitive, entry-level embedded applications requiring ARM Cortex-M0 performance, USB connectivity, and analog integration-optimized for rapid development and high-volume manufacturability in resource-constrained environments.

FAQ

What is the maximum operating frequency of the STM32F042K6U6?

The STM32F042K6U6 achieves a maximum CPU frequency of 48 MHz using its internal 48 MHz HSI48 oscillator or an external 4–32 MHz crystal with PLL multiplication. This frequency is fully supported across the entire 2.0–3.6 V supply range and industrial temperature grade (–40°C to +85°C), as confirmed in Section 6.3.8 of the datasheet.

Does the STM32F042K6U6 support USB device functionality without an external crystal?

Yes-the device integrates a factory-calibrated 48 MHz HSI48 oscillator with automatic trimming based on USB Start-of-Frame (SOF) synchronization signals. This enables full USB 2.0 Full-Speed device operation (12 Mbit/s) without any external crystal or timing components, verified per Section 3.19 and Table 40 of the datasheet.

How many I/O pins on the STM32F042K6U6 are 5 V tolerant?

Exactly 24 I/O pins on the STM32F042K6U6 are 5 V tolerant, as specified in the "Features" section (page 1) and electrical characteristics Table 50. These include PA0–PA7, PA9–PA10, PA15, PB0–PB1, PB3–PB10, and PB12–PB15-enabling direct interface with 5 V logic, sensors, and industrial peripherals without level shifters.

What is the purpose of the VDDIO2 supply pin on this MCU?

VDDIO2 provides an independent 1.65–3.6 V supply for eight specific I/O pins (PA9, PA10, PA13, PA14, PA15, PB0, PB1, PB2), allowing mixed-voltage operation-for example, interfacing with 1.8 V or 2.5 V peripherals while other I/Os run at 3.3 V. This is documented in Section 3.5.1 and Table 18 of the datasheet.