STMicroelectronics STM32F042K4U6

Overview

STM32F042K4U6 from STMicroelectronics is an ARM® Cortex®-M0 32-bit microcontroller with 16 KB Flash, 6 KB SRAM, crystal-less USB 2.0 FS interface, CAN 2.0B controller, and 48 MHz max CPU frequency. It integrates a 12-bit ADC (1.0 µs conversion), nine timers including one advanced-control timer for six-channel PWM, and operates from 2.0–3.6 V supply. Used in industrial sensor nodes requiring integrated USB-CDC communication and CAN bus interfacing.

For engineers reviewing the STM32F042K4U6 datasheet, STM32F042K4U6 pinout, STM32F042K4U6 application, or STM32F042K4U6 equivalent, key selection criteria include USB 2.0 FS operation without external crystal, CAN transceiver compatibility, 5 V-tolerant I/O count (up to 24), internal 48 MHz oscillator trimming, and support for capacitive touch sensing on up to 14 channels.

Technical Context

The STM32F042K4U6 implements a single-cycle ARM Cortex-M0 core with NVIC supporting 32 interrupts and nested priority handling. Its clock system includes dual oscillators - a 4–32 MHz HSE for precision timing and a factory-trimmed 48 MHz HSI48 specifically for USB frame synchronization without external crystal.

Peripheral integration centers on mixed-signal coexistence: the 12-bit ADC shares VDDA (2.4–3.6 V) with independent analog supply routing, while the TSC (touch sensing controller) uses dedicated GPIOs with hardware-accelerated charge-transfer measurement. The CAN controller supports bit rates up to 1 Mbit/s and conforms to ISO 11898-1.

Key Specifications

Pinout & Package

STM32F042K4U6 is housed in a 32-pin UFQFPN package (5 × 5 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per STMicroelectronics DocID025832 Rev 5, Section 4 (Pinouts and pin descriptions).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM32F042K4U6, the K6U6 offers headroom for complex USB device classes (e.g., HID+MSC composite), while the F072K6T6 trades Flash margin for extended temperature resilience - both retain identical USB crystal-less operation and CAN timing accuracy.

Availability

STM32F042K4U6 is available at Aetrix Electronics and suitable for industrial sensor nodes, USB-CDC gateways, capacitive touch interfaces, and smart power outlets requiring stable component supply across multi-year production cycles.

Supply support for STM32F042K4U6 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, specializing in microcontrollers, power management, and automotive ICs with over 40 years of industrial-grade reliability.

The STM32F0 series targets cost-sensitive, resource-constrained embedded applications requiring USB connectivity, analog integration, and low-power operation - optimized for industrial controls, appliance HMI, and sensor edge nodes.

FAQ

Does STM32F042K4U6 support USB device enumeration without an external crystal?

Yes. It features an internal 48 MHz HSI48 oscillator with automatic trimming based on USB Start-of-Frame (SOF) packets, enabling full-speed USB 2.0 device enumeration and data transfer without any external crystal or resonator. This is confirmed in Section 3.6 and Table 40 of the official datasheet (DocID025832 Rev 5).

What is the maximum number of 5 V-tolerant I/Os on STM32F042K4U6?

The device supports up to 24 5 V-tolerant I/Os across GPIO ports A, B, and F. These pins tolerate 5 V regardless of VDD level (2.0–3.6 V) and are explicitly listed in Table 5 of the datasheet. Not all 32 pins are 5 V tolerant - only those designated with "FT" (fail-safe tolerant) marking in the pin description table.

Can the STM32F042K4U6's TSC operate simultaneously with the ADC?

No. The Touch Sensing Controller (TSC) and ADC share the same analog front-end resources, including the VREFINT reference and certain GPIO channels (e.g., PA0 serves as both ADC1_IN0 and TSC_CH1). Concurrent operation is not supported; time-multiplexed use is required, with careful sequencing of clock gating and calibration routines.

Is the CAN controller compatible with standard ISO 11898-1 physical layer transceivers?

Yes. The integrated CAN 2.0B controller complies with ISO 11898-1 and supports bit rates up to 1 Mbit/s. It requires an external CAN transceiver (e.g., TJA1042, SN65HVD230) for physical layer signaling. The PB8/PB9 pins provide direct TX/RX signals with configurable slew rate and filtering, validated per Section 3.18 of the datasheet.