STM32F042F6P6 from STMicroelectronics, in a TSSOP-20. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	PB8/BOOT0	bidirectional	General-purpose I/O (FTf: 5V-tolerant, Fast-Mode+ I2C capable). Also serves as BOOT0 pin to select boot memory (main Flash / system memory / embedded SRAM). Alternate functions: I2C1_SCL, CEC, TIM16_CH1, TSC_SYNC, CAN_RX.
2	PF0-OSC_IN	bidirectional	5V-tolerant, FM+ capable I/O. Additional function: HSE crystal oscillator input (OSC_IN). Alternate functions: CRS_SYNC, I2C1_SDA.
3	PF1-OSC_OUT	bidirectional	5V-tolerant, FM+ capable I/O. Additional function: HSE crystal oscillator output (OSC_OUT). Alternate function: I2C1_SCL.
4	NRST	bidirectional	Device reset input / internal reset output (active low). Bidirectional pin with embedded weak pull-up resistor (RST I/O structure).
5	VDDA	power_in	Analog power supply, 2.0 - 3.6 V. Powers the ADC, reset block, PLL and internal regulator analog sections.
6	PA0	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional functions: RTC_TAMP2, WKUP1, ADC_IN0. Alternate functions: USART2_CTS, TIM2_CH1_ETR, TSC_G1_IO1.
7	PA1	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN1. Alternate functions: EVENTOUT, USART2_RTS, TIM2_CH2, TSC_G1_IO2.
8	PA2	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional functions: ADC_IN2, WKUP4. Alternate functions: USART2_TX, TIM2_CH3, TSC_G1_IO3.
9	PA3	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN3. Alternate functions: USART2_RX, TIM2_CH4, TSC_G1_IO4.
10	PA4	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN4. Alternate functions: SPI1_NSS, I2S1_WS, TIM14_CH1, TSC_G2_IO1, USART2_CK, USB_NOE.
11	PA5	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN5. Alternate functions: SPI1_SCK, I2S1_CK, CEC, TIM2_CH1_ETR, TSC_G2_IO2.
12	PA6	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN6. Alternate functions: SPI1_MISO, I2S1_MCK, TIM3_CH1, TIM1_BKIN, TIM16_CH1, TSC_G2_IO3, EVENTOUT.
13	PA7	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN7. Alternate functions: SPI1_MOSI, I2S1_SD, TIM3_CH2, TIM14_CH1, TIM1_CH1N, TIM17_CH1, TSC_G2_IO4, EVENTOUT.
14	PB1	bidirectional	TTa I/O (3.3 V-tolerant, ADC-connected). Additional function: ADC_IN9. Alternate functions: TIM3_CH4, TIM14_CH1, TIM1_CH3N, TSC_G3_IO3.
15	VSS	power_in	Digital ground. On TSSOP20 (and all non-48-pin packages) VSSA (analog ground) is bonded internally to this VSS pin; both digital and analog grounds must be connected here.
16	VDD	power_in	Digital power supply, 2.0 - 3.6 V. On TSSOP20 this pin is shared with VDDIO2 (supply for PA8-PA15 I/Os); both are bonded to the same package pin.
17	PA9	bidirectional	FTf I/O (5V-tolerant, FM+ capable), powered by VDDIO2. Alternate functions: USART1_TX, TIM1_CH2, TSC_G4_IO1, I2C1_SCL, MCO. PA11 can be remapped to this pin via SYSCFG_CFGR1.
18	PA10	bidirectional	FTf I/O (5V-tolerant, FM+ capable), powered by VDDIO2. Alternate functions: USART1_RX, TIM1_CH3, TIM17_BKIN, TSC_G4_IO2, I2C1_SDA. PA12 can be remapped to this pin via SYSCFG_CFGR1.
19	PA13	bidirectional	FT I/O (5V-tolerant), powered by VDDIO2. After reset configured as SWDIO with internal pull-up. Alternate functions: SWDIO, IR_OUT, USB_NOE.
20	PA14	bidirectional	FT I/O (5V-tolerant), powered by VDDIO2. After reset configured as SWCLK with internal pull-down. Alternate functions: SWCLK, USART2_TX.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	TSSOP-20
Category	MCU
Pins	20

Ordering variants

Same part, different packaging or reel option.

STM32F042F6P6
STM32F042F6P6F4P6
STM32F042F6P6F6P7
STM32F042F6P6F4P7
STM32F042F6P6G6U6
STM32F042F6P6G4U6
STM32F042F6P6T6Y6
STM32F042F6P6T4Y6
STM32F042F6P6K6T6
STM32F042F6P6K4T6
STM32F042F6P6K6U6
STM32F042F6P6K4U6
STM32F042F6P6C6T6
STM32F042F6P6C4T6
STM32F042F6P6C6U6
STM32F042F6P6C4U6

CAD (KiCad official)

Symbol: STM32F042F6P6
Footprint: Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm
3D model: TSSOP-20 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`stm32f042f6p6.step`	267 KB	You want the bare part, or you mark your own boards.
`stm32f042f6p6-etched.step`	3.4 MB	You want the part with `STM32F042F6P6` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 822 faces against 327 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: STMicroelectronics datasheet (118 pp, sha256 4c7b3ccc0428dbff, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF