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Contents

README

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STM8S103F3U3TR

STMicroelectronics · Microcontroller Units (MCUs/MPUs/SOCs) · UFQFPN-20(3x3)

STM8S103F3U3TR from STMicroelectronics, in a UFQFPN-20(3x3). Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 NRST bidirectional Reset input with internal weak pull-up, active low.
2 PA1/OSCIN bidirectional General-purpose I/O port A1, external oscillator crystal input.
3 PA2/OSCOUT bidirectional General-purpose I/O port A2, external oscillator crystal output.
4 VSS power_in Digital ground.
5 VCAP passive 1.8 V internal regulator output capacitor connection.
6 VDD power_in Digital power supply, 2.95 to 5.5 V.
7 PA3/TIM2_CH3 bidirectional High sink I/O port A3, Timer 2 channel 3 or configurable as SPI slave select via alternate function remapping.
8 PB5/I2C_SDA tri_state True open-drain I/O port B5, I2C data or configurable as Timer 1 break input via alternate function remapping.
9 PB4/I2C_SCL tri_state True open-drain I/O port B4, I2C clock or configurable as ADC external trigger via alternate function remapping.
10 PC3/TIM1_CH3 bidirectional High sink I/O port C3, Timer 1 channel 3 or configurable as top-level interrupt or inverted Timer 1 channel 1 via alternate function remapping.
11 PC4/CLK_CCO/TIM1_CH4/AIN2 bidirectional High sink I/O port C4, configurable as clock output, Timer 1 channel 4, analog input 2, or inverted Timer 1 channel 2 via alternate function remapping.
12 PC5/SPI_SCK bidirectional High sink I/O port C5, SPI clock or configurable as Timer 2 channel 1 via alternate function remapping.
13 PC6/SPI_MOSI bidirectional High sink I/O port C6, SPI master out/slave in or configurable as Timer 1 channel 1 via alternate function remapping.
14 PC7/SPI_MISO bidirectional High sink I/O port C7, SPI master in/slave out or configurable as Timer 1 channel 2 via alternate function remapping.
15 PD1/SWIM bidirectional High sink I/O port D1, SWIM single-wire interface for in-circuit debugging and programming.
16 PD2/AIN3 bidirectional High sink I/O port D2, analog input 3 or configurable as Timer 2 channel 3 via alternate function remapping.
17 PD3/AIN4/TIM2_CH2/ADC_ETR bidirectional High sink I/O port D3, analog input 4, Timer 2 channel 2, or ADC external trigger.
18 PD4/BEEP/TIM2_CH1/UART1_CK bidirectional High sink I/O port D4, configurable as beeper output, Timer 2 channel 1, or UART1 clock.
19 PD5/AIN5/UART1_TX bidirectional High sink I/O port D5, UART1 transmit data or analog input 5.
20 PD6/AIN6/UART1_RX bidirectional High sink I/O port D6, UART1 receive data or analog input 6.

Key specifications

Parameter Value
Manufacturer STMicroelectronics
Package UFQFPN-20(3x3)
Category Single Chip Microcomputer/Microcontroller
Pins 20

CAD (KiCad official)

  • Symbol: STM8S103F3U3TR
  • Footprint: Package_DFN_QFN:ST_UFQFPN-20_3x3mm_P0.5mm
  • 3D model: UFQFPN-20(3x3) (KiCad packages3D, STEP)
  • 3D model files: stm8s103f3u3tr-etched.step / stm8s103f3u3tr-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); stm8s103f3u3tr.step / stm8s103f3u3tr.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: STMicroelectronics datasheet (121 pp, sha256 ac23789ac0a2f408, retrieved 2026-10-07, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-4-5-20251001 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF