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Contents

README

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STM32L021D4P7

STMicroelectronics · Microcontrollers (MCU/MPU/SOC) · TSSOP-14

STM32L021D4P7 from STMicroelectronics, in a TSSOP-14. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model, then checked against ST open pin data); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 PB9-BOOT0 input Boot memory selection input (BOOT0), active high, determines boot from Flash or system bootloader
2 PC14-OSC32_IN bidirectional 32 kHz oscillator input for RTC, supports OSC32_IN function for external crystal connection
3 PC15-OSC32_OUT bidirectional 32 kHz oscillator output for RTC, supports OSC32_OUT function for external crystal connection
4 NRST bidirectional Device reset input/output (active low) with embedded weak pull-up resistor, 5V tolerant
5 PA0-CK_IN bidirectional Port A bit 0, ADC channel 0, 3.3V tolerant ADC input, supports alternate functions USART2_RX, LPTIM1_IN1, TIM2_CH1, LPUART1_RX, COMP1_OUT
6 PA1 bidirectional Port A bit 1, ADC channel 1, 5V tolerant I/O, supports alternate functions LPTIM1_IN2, TIM2_CH2, I2C1_SMBA, USART2_RTS_DE, LPUART1_TX, COMP1_INP
7 PA4 bidirectional Port A bit 4, ADC channel 4, 3.3V tolerant ADC input, supports alternate functions SPI1_NSS, LPTIM1 inputs, I2C1_SCL, USART2_CK, LPUART1_TX, COMP2_OUT
8 PA7 bidirectional Port A bit 7, ADC channel 7, 5V tolerant I/O, supports alternate functions SPI1_MOSI, LPTIM1_OUT, USART2_CTS, TIM21_ETR, COMP2_OUT, COMP2_INP
9 VSS power_in Digital and analog ground (GND)
10 VDD power_in Digital and analog power supply, 1.65V to 3.6V, internally connected to VDDA on TSSOP14 variant
11 PA9 bidirectional Port A bit 9, 5V tolerant FM+ capable I/O with 20mA output drive, supports MCO, I2C1_SCL, LPTIM1_OUT, USART2_TX, TIM21_CH2, COMP1_OUT
12 PA10 bidirectional Port A bit 10, 5V tolerant FM+ capable I/O with 20mA output drive, supports TIM21_CH1, I2C1_SDA, USART2_RX, TIM2_CH3, COMP1_OUT, RTC_REFIN
13 PA13 bidirectional Port A bit 13, 5V tolerant FM+ capable I/O, Serial Wire Debug Data I/O (SWDIO), supports alternate functions LPTIM1_ETR, I2C1_SDA, SPI1_SCK, LPUART1_RX, COMP1_OUT
14 PA14 bidirectional Port A bit 14, 5V tolerant I/O, Serial Wire Debug Clock (SWCLK), acts as SPI1_MISO when bootloader active, supports LPTIM1_OUT, I2C1_SMBA, USART2_TX, LPUART1_TX, COMP2_OUT

Key specifications

Parameter Value
Manufacturer STMicroelectronics
Package TSSOP-14
Category Embedded Processors & Controllers
Pins 14

CAD (KiCad official)

  • Symbol: STM32L021D4P7
  • Footprint: Package_SO:TSSOP-14_4.4x5mm_P0.65mm
  • 3D model: TSSOP-14 (KiCad packages3D, STEP)
  • 3D model files: stm32l021d4p7-etched.step / stm32l021d4p7-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); stm32l021d4p7.step / stm32l021d4p7.glb are the bare package body.

Provenance

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

  • Datasheet: STMicroelectronics datasheet (114 pp, sha256 97b23667dad711b9, retrieved 2026-10-06, 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