This part is a kind of semiconductor called STM8S903K3.

Function of this product has (STM8S903K3 / STM8S903F3) 16 MHz STM8S 8-bit MCU.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

STM8S903K3 STM8S903F3 16 MHz STM8S 8-bit MCU, up to 8 Kbytes Flash, 1 Kbyte RAM, 640 bytes EEPROM,10-bit ADC, 2 timers, UART, SPI, I²C - Switch-off peripheral clocks individually active, low consumption power-on • Permanently and power-down reset Interrupt management Nested interrupt controller with 32 interrupts LQFP32 7x7 UFQFPN32 5x5 SDIP32 400 mils • • Up to 28 external interrupts on 7 vectors • Timers Advanced control timer: 16-bit, 4 CAPCOM channels, 3 complementary outputs, dead-time insertion and flexible synchronization TSSOP20 UFQFPN20 3x3 SO20W 300 mils Features general purpose timer, with 3 CAPCOM • 16-bit channels (IC, OC or PWM) • 8-bit basic timer with 8-bit prescaler • Auto wakeup timer • Window and independent watchdog timers Communications interfac [ ... ]

STM8S903K3 PDF Datasheet Download