STC8H1K08-36I-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/SS/T2/PWM2P	bidirectional	General-purpose I/O P1.2. Muxed alternate functions: SPI slave-select (SS), Timer 2 external clock input (T2), advanced PWM2 capture input / positive pulse output (PWM2P).
2	P1.3/MOSI/T2CLKO/PWM2N	bidirectional	General-purpose I/O P1.3. Alternate functions: SPI MOSI, Timer 2 clock divide output (T2CLKO), advanced PWM2 negative pulse output (PWM2N).
3	P1.4/MISO/SDA/PWM3P	bidirectional	General-purpose I/O P1.4. Alternate functions: SPI MISO, I2C data line (SDA), advanced PWM3 capture input / positive pulse output (PWM3P).
4	P1.5/SCLK/SCL/PWM3N	bidirectional	General-purpose I/O P1.5. Alternate functions: SPI clock (SCLK), I2C clock line (SCL), advanced PWM3 negative pulse output (PWM3N).
5	P1.6/RxD_3/PWM4P/MCLKO_2/XTALO	bidirectional	General-purpose I/O P1.6. Alternate functions: UART1 receive (RxD_3 alternate mapping), advanced PWM4 capture/positive pulse output (PWM4P), master clock divide output (MCLKO_2), external crystal output (XTALO).
6	P1.7/TxD_3/PWM4N/PWM5_2/XTALI	bidirectional	General-purpose I/O P1.7. Alternate functions: UART1 transmit (TxD_3 alternate mapping), PWM4 negative pulse output (PWM4N), PWM5 alternate mapping (PWM5_2), external crystal/clock input (XTALI).
7	P5.4/nRST/MCLKO/PWM6_2	bidirectional	General-purpose I/O P5.4 doubling as active-low reset input (nRST). Also usable as master clock divide output (MCLKO) or PWM6 alternate mapping (PWM6_2). Factory default is I/O mode; enable nRST via ISP.
8	VCC/AVCC	power_in	Main supply and analog supply, tied internally. Operating range 1.9-5.5 V. Bypass with 10 µF bulk plus 0.1 µF decoupling to GND near the pin.
9	ADC_VRef+	input	ADC positive reference input. Must be driven from an external reference (2.4 V to VCC); may be tied directly to VCC when high accuracy is not required. Floating causes leakage current.
10	GND/AGND	power_in	Ground return for both the digital core and the analog / ADC block, tied internally.
11	P3.0/ADC8/RxD/INT4	bidirectional	General-purpose I/O P3.0. Alternate functions: ADC channel 8, UART1 receive (RxD, default mapping), external interrupt 4 (INT4). Powers up as weak pull-up (quasi-bidirectional).
12	P3.1/ADC9/TxD	bidirectional	General-purpose I/O P3.1. Alternate functions: ADC channel 9, UART1 transmit (TxD, default mapping). Powers up as weak pull-up (quasi-bidirectional).
13	P3.2/ADC10/INT0/SCLK_4/SCL_4/PWMETI/PWMETI2	bidirectional	General-purpose I/O P3.2. Alternate functions: ADC channel 10, external interrupt 0 (INT0), SPI clock alternate mapping 4 (SCLK_4), I2C clock alternate mapping 4 (SCL_4), advanced PWM external trigger inputs (PWMETI, PWMETI2).
14	P3.3/ADC11/INT1/MISO_4/SDA_4/PWM4N_4/PWM7_2	bidirectional	General-purpose I/O P3.3. Alternate functions: ADC channel 11, external interrupt 1 (INT1), SPI MISO alternate mapping 4, I2C SDA alternate mapping 4, PWM4 negative output alternate mapping, PWM7 alternate mapping.
15	P3.4/ADC12/T0/T1CLKO/MOSI_4/PWM4P_4/PWM8_2/CMPO	bidirectional	General-purpose I/O P3.4. Alternate functions: ADC channel 12, Timer 0 external clock input (T0), Timer 1 clock divide output (T1CLKO), SPI MOSI alt-map 4, PWM4/PWM8 alt-map outputs, 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 clock input (T1), Timer 0 clock divide output (T0CLKO), SPI slave select alt-map 4 (SS_4), PWMA/PWMB external fault detect 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 2 (INT2), UART1 receive alt-map 2 (RxD_2), analog comparator negative input (CMP-).
18	P3.7/INT3/TxD_2/CMP+	bidirectional	General-purpose I/O P3.7. Alternate functions: external interrupt 3 (INT3), UART1 transmit alt-map 2 (TxD_2), analog comparator positive input (CMP+).
19	P1.0/ADC0/RxD2/PWM1P	bidirectional	General-purpose I/O P1.0. Alternate functions: ADC channel 0, UART2 receive (RxD2), advanced PWM1 capture/positive pulse output (PWM1P).
20	P1.1/ADC1/TxD2/PWM1N	bidirectional	General-purpose I/O P1.1. Alternate functions: ADC channel 1, UART2 transmit (TxD2), advanced PWM1 negative pulse 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.

STC8H1K08-36I-TSSOP20
STC8H1K08-36I-QFN20
STC8H1K08-36I-SOP20
STC8H1K08-36I-SOP16

CAD (KiCad official)

Symbol: STC8H1K08-36I-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
`stc8h1k08-36i-tssop20.step`	267 KB	You want the bare part, or you mark your own boards.
`stc8h1k08-36i-tssop20-etched.step`	4.8 MB	You want the part with `STC8H1K08-36I-TSSOP20` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 1149 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