STM8S105K4T6C from STMicroelectronics, in a LQFP-32(7x7). 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	NRST	bidirectional	Active-low reset input/output. Bidirectional pin - asserted low by internal reset sources (POR, watchdog, SWIM) and can be driven low externally to reset the device. Includes an internal pull-up.
2	PA1/OSC_IN	bidirectional	Port A bit 1 GPIO with weak pull-up option, slow (2 MHz) push-pull or open-drain output. Alternate function: resonator/crystal input (OSC_IN) for the external clock oscillator.
3	PA2/OSC_OUT	bidirectional	Port A bit 2 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Alternate function: resonator/crystal output (OSC_OUT) for the external oscillator.
4	VSS	power_in	Digital ground reference for the STM8 core and digital peripherals.
5	VCAP	power_in	Output of the internal 1.8 V regulator that supplies the core logic. Requires an external stabilization capacitor (typically 1 µF ceramic) to VSS. Do not connect to any external supply.
6	VDD	power_in	Digital power supply (2.95 V to 5.5 V) for the STM8 core and digital peripherals. Decouple locally with a 100 nF ceramic capacitor to VSS.
7	VDDIO_1	power_in	I/O power supply (2.95 V to 5.5 V) for one bank of GPIO output buffers. Should be tied to VDD in typical single-supply designs and decoupled with a 100 nF ceramic capacitor.
8	PF4/AIN12	bidirectional	Port F bit 4 GPIO with weak pull-up option, slow (2 MHz) push-pull or open-drain output. Alternate function: ADC analog input channel 12 (AIN12). Has an active pull-up during reset phase; floats after reset release.
9	VDDA	power_in	Analog power supply (2.95 V to 5.5 V) for the 10-bit ADC and internal analog reference. Recommend a ferrite or LC filter from VDD and a 100 nF + 1 µF decoupling network to VSSA.
10	VSSA	power_in	Analog ground reference for the ADC and analog circuitry. Should be joined to VSS at a single star point near the MCU for best ADC accuracy.
11	PB5/AIN5/[I2C_SDA]	bidirectional	Port B bit 5 GPIO with external interrupt capability, weak pull-up option, slow (2 MHz) push-pull or open-drain output. Default alternate function: ADC analog input 5 (AIN5). Remap alternate (AFR6): I²C serial data (I2C_SDA).
12	PB4/AIN4/[I2C_SCL]	bidirectional	Port B bit 4 GPIO with external interrupt capability, weak pull-up option, slow (2 MHz) push-pull or open-drain output. Default alternate: ADC analog input 4 (AIN4). Remap alternate (AFR6): I²C serial clock (I2C_SCL).
13	PB3/AIN3/[TIM1_ETR]	bidirectional	Port B bit 3 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Default alternate: ADC analog input 3 (AIN3). Remap alternate (AFR5): TIM1 external trigger input (TIM1_ETR).
14	PB2/AIN2/[TIM1_CH3N]	bidirectional	Port B bit 2 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Default alternate: ADC analog input 2 (AIN2). Remap alternate (AFR5): TIM1 complementary channel 3 output (TIM1_CH3N).
15	PB1/AIN1/[TIM1_CH2N]	bidirectional	Port B bit 1 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Default alternate: ADC analog input 1 (AIN1). Remap alternate (AFR5): TIM1 complementary channel 2 output (TIM1_CH2N).
16	PB0/AIN0/[TIM1_CH1N]	bidirectional	Port B bit 0 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Default alternate: ADC analog input 0 (AIN0). Remap alternate (AFR5): TIM1 complementary channel 1 output (TIM1_CH1N).
17	PE5/SPI_NSS	bidirectional	Port E bit 5 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Alternate function: SPI master/slave select (SPI_NSS).
18	PC1/TIM1_CH1/UART2_CK	bidirectional	Port C bit 1 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast (10 MHz) programmable push-pull or open-drain output. Alternate functions: TIM1 channel 1 (TIM1_CH1) or UART2 synchronous clock (UART2_CK).
19	PC2/TIM1_CH2	bidirectional	Port C bit 2 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Alternate function: TIM1 channel 2 (TIM1_CH2).
20	PC3/TIM1_CH3	bidirectional	Port C bit 3 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Alternate function: TIM1 channel 3 (TIM1_CH3).
21	PC4/TIM1_CH4	bidirectional	Port C bit 4 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable open-drain output. Alternate function: TIM1 channel 4 (TIM1_CH4).
22	PC5/SPI_SCK	bidirectional	Port C bit 5 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Alternate function: SPI clock (SPI_SCK).
23	PC6/SPI_MOSI	bidirectional	Port C bit 6 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Alternate function: SPI master-out/slave-in (SPI_MOSI).
24	PC7/SPI_MISO	bidirectional	Port C bit 7 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Alternate function: SPI master-in/slave-out (SPI_MISO).
25	PD0/TIM3_CH2/[TIM1_BKIN]/[CLK_CCO]	bidirectional	Port D bit 0 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Default alternate: TIM3 channel 2 (TIM3_CH2). Remap alternates: TIM1 break input (TIM1_BKIN, AFR3) or configurable clock output (CLK_CCO, AFR2).
26	PD1/SWIM	bidirectional	Port D bit 1 GPIO with external interrupt capability, high-sink drive, fast programmable output (fast as default state after reset). Alternate function: Single Wire Interface Module (SWIM) - the ST programming/debug interface used with ST-LINK. In input pull-up during reset and after reset release.
27	PD2/TIM3_CH1/[TIM2_CH3]	bidirectional	Port D bit 2 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Default alternate: TIM3 channel 1 (TIM3_CH1). Remap alternate (AFR1): TIM2 channel 3 (TIM2_CH3).
28	PD3/TIM2_CH2/[ADC_ETR]	bidirectional	Port D bit 3 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Default alternate: TIM2 channel 2 (TIM2_CH2). Remap alternate (AFR0): ADC external trigger (ADC_ETR).
29	PD4/TIM2_CH1/[BEEP]	bidirectional	Port D bit 4 GPIO with external interrupt capability, high-sink drive, weak pull-up option, fast programmable push-pull or open-drain output. Default alternate: TIM2 channel 1 (TIM2_CH1). Remap alternate (AFR7): BEEP output.
30	PD5/UART2_TX	bidirectional	Port D bit 5 GPIO with external interrupt capability, weak pull-up option, slow (2 MHz) push-pull or open-drain output. Alternate function: UART2 data transmit (UART2_TX).
31	PD6/UART2_RX	bidirectional	Port D bit 6 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Alternate function: UART2 data receive (UART2_RX).
32	PD7/TLI/[TIM1_CH4]	bidirectional	Port D bit 7 GPIO with external interrupt capability, weak pull-up option, slow push-pull or open-drain output. Default alternate: top level interrupt (TLI). Remap alternate (AFR4): TIM1 channel 4 (TIM1_CH4).

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	LQFP-32(7x7)
Category	Embedded Processors & Controllers
Pins	32

Ordering variants

Same part, different packaging or reel option.

STM8S105K4T6C
STM8S105K4T6CK6T6
STM8S105K4T6CK6T6C
STM8S105K4T6CK4U6
STM8S105K4T6CK6U6
STM8S105K4T6CS4T6
STM8S105K4T6CS6T6
STM8S105K4T6CC4T6
STM8S105K4T6CC6T6

CAD (KiCad official)

Symbol: STM8S105K4T6C
Footprint: Package_QFP:LQFP-32_7x7mm_P0.8mm
3D model: LQFP-32(7x7) (KiCad packages3D, STEP)

Provenance

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

Datasheet: STMicroelectronics datasheet (99 pp, sha256 9cd29ad29b7c0ce9, retrieved 2026-08-17, tier: lcsc)
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