STC8H1K17-36I-TSSOP20 from STC Micro, 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	P1.2/T2/SS/PWM2P	bidirectional	General-purpose I/O P1.2. Muxed functions: Timer 2 external clock/gate input (T2), SPI slave-select (SS), advanced PWM channel 2 positive output (PWM2P).
2	P1.3/T2CLKO/MOSI/PWM2N	bidirectional	General-purpose I/O P1.3. Alternate functions: Timer 2 clock output (T2CLKO), SPI master-out/slave-in (MOSI), advanced PWM channel 2 negative output (PWM2N).
3	P1.4/I2CSDA/MISO/PWM3P	bidirectional	General-purpose I/O P1.4. Alternate functions: I2C data (SDA), SPI master-in/slave-out (MISO), advanced PWM channel 3 positive output (PWM3P).
4	P1.5/I2CSCL/SCLK/PWM3N	bidirectional	General-purpose I/O P1.5. Alternate functions: I2C clock (SCL), SPI clock (SCLK), advanced PWM channel 3 negative output (PWM3N).
5	P1.6/XTALO/MCLKO_2/RxD_3/PWM4P	bidirectional	General-purpose I/O P1.6. Alternate functions: external crystal oscillator output (XTALO), master-clock output alt-2 (MCLKO_2), UART1 RxD alternate-3, advanced PWM channel 4 positive output (PWM4P).
6	P1.7/XTALI/TxD_3/PWM5_2/PWM4N	bidirectional	General-purpose I/O P1.7. Alternate functions: external crystal oscillator input (XTALI), UART1 TxD alternate-3, PWM channel 5 alt-2, advanced PWM channel 4 negative output (PWM4N).
7	P5.4/MCLKO/PWM6_2/nRST	bidirectional	GPIO P5.4 by factory default; can be configured via ISP option as the active-low external reset input (nRST). Alternate functions: master-clock output (MCLKO), PWM channel 6 alt-2. Internal 4 kΩ pull-up is always enabled when configured as nRST; when used as I/O the pull-up stays on for ~6.5 ms after power-up before automatically releasing.
8	VCC/AVCC	power_in	Digital and analog supply input, 1.9 V to 5.5 V. Decouple with a ≥10 µF bulk capacitor plus a 0.1 µF ceramic between VCC and GND placed close to the pin.
9	ADC_VREF+	power_in	External ADC positive reference input. Must be driven by an external reference between 2.4 V and VCC when the ADC is used; if left floating it will exhibit leakage current.
10	GND/AGND	power_in	Common digital and analog ground return.
11	P3.0/ADC8/RxD/INT4	bidirectional	General-purpose I/O P3.0. Powers up as quasi-bidirectional with weak pull-up (default UART download RxD pin). Alternate functions: ADC channel 8, UART1 receive (RxD), external interrupt INT4 (falling-edge only).
12	P3.1/ADC9/TxD	bidirectional	General-purpose I/O P3.1. Powers up as quasi-bidirectional with weak pull-up (default UART download TxD pin). Alternate functions: ADC channel 9, UART1 transmit (TxD).
13	P3.2/ADC10/INT0/SCLK_4/I2CSCL_4/PWMETI/PWMETI2	bidirectional	General-purpose I/O P3.2. Alternate functions: ADC channel 10, external interrupt INT0 (rising/falling edge), SPI clock alt-4, I2C clock alt-4, PWMA/PWMB external trigger inputs (PWMETI, PWMETI2).
14	P3.3/ADC11/INT1/MISO_4/I2CSDA_4/PWM4N_2/PWM7_2	bidirectional	General-purpose I/O P3.3. Alternate functions: ADC channel 11, external interrupt INT1 (rising/falling edge), SPI MISO alt-4, I2C SDA alt-4, PWM4N alt-2, PWM7 alt-2.
15	P3.4/ADC12/T0/T1CLKO/MOSI_4/PWM4P_2/PWM8_2/CMPO	bidirectional	General-purpose I/O P3.4. Alternate functions: ADC channel 12, Timer 0 external input (T0), Timer 1 clock output (T1CLKO), SPI MOSI alt-4, PWM4P alt-2, PWM8 alt-2, analog comparator output (CMPO).
16	P3.5/ADC13/T1/T0CLKO/SS_4/PWMFLT/PWMFLT2	bidirectional	General-purpose I/O P3.5. Alternate functions: ADC channel 13, Timer 1 external input (T1), Timer 0 clock output (T0CLKO), SPI slave-select alt-4, PWMA/PWMB fault inputs (PWMFLT, PWMFLT2).
17	P3.6/ADC14/INT2/RxD_2/CMP-	bidirectional	General-purpose I/O P3.6. Alternate functions: ADC channel 14, external interrupt INT2 (falling edge only), UART1 receive alt-2 (RxD_2), analog comparator inverting input (CMP-).
18	P3.7/INT3/TxD_2/CMP+	bidirectional	General-purpose I/O P3.7. Alternate functions: external interrupt INT3 (falling edge only), UART1 transmit alt-2 (TxD_2), analog comparator non-inverting input (CMP+).
19	P1.0/ADC0/RxD2/PWM1P	bidirectional	General-purpose I/O P1.0. Alternate functions: ADC channel 0, UART2 receive (RxD2), advanced PWM channel 1 positive output (PWM1P).
20	P1.1/ADC1/TxD2/PWM1N	bidirectional	General-purpose I/O P1.1. Alternate functions: ADC channel 1, UART2 transmit (TxD2), advanced PWM channel 1 negative output (PWM1N).

Key specifications

Parameter	Value
Manufacturer	STC Micro
Package	TSSOP-20
Category	MCU
Pins	20

Ordering variants

Same part, different packaging or reel option.

STC8H1K17-36I-TSSOP20
STC8H1K17-36I-SOP20
STC8H1K17-36I-QFN20
STC8H1K17-36I-SOP16

CAD (KiCad official)

Symbol: STC8H1K17-36I-TSSOP20
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
`stc8h1k17-36i-tssop20.step`	267 KB	You want the bare part, or you mark your own boards.
`stc8h1k17-36i-tssop20-etched.step`	4.4 MB	You want the part with `STC8H1K17-36I-TSSOP20` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 1067 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: STC Micro datasheet (2180 pp, sha256 046aea020e4685f3, 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