STM  -  Series DataSheet
STM8S903K3  -  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  -  STMicroelectronics  -  STM8

Features
Core
■ 16 MHz advanced STM8 core with Harvard architecture and 3-stage pipeline
■ Extended instruction set
Memories
■ Program memory: 8 Kbytes Flash; data retention 20 years at 55 °C after 10 kcycles
■ Data memory: 640 bytes true data EEPROM; endurance 300 kcycles
■ RAM: 1 Kbytes
Clock, reset and supply management
■ 2.95 to 5.5 V operating voltage
■ Flexible clock control, 4 master clock sources:
– Low power crystal resonator oscillator
– External clock input
– Internal, user-trimmable 16 MHz RC
– Internal low power 128 kHz RC
■ Clock security system with clock monitor
■ Power management:
– Low power modes (wait, active-halt, halt)
– Switch-off peripheral clocks individually
■ Permanently active, low consumption poweron and power-down reset
Interrupt management
■ Nested interrupt controller with 32 interrupts
■ 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
■ 16-bit general purpose timer, with 3 CAPCOM channels (IC, OC or PWM)
■ 8-bit basic timer with 8-bit prescaler
■ Auto wake-up timer
■ 2 watchdog timers: Window watchdog and independent watchdog
Communications interfaces
■ UART with clock output for synchronous operation, Smartcard, IrDA, LIN master mode
■ SPI interface up to 8 Mbit/s
■ I2C interface up to 400 Kbit/s
Analog to digital converter (ADC)
■ 10-bit, ±1 LSB ADC with up to 7 multiplexed channels + 1 internal channel, scan mode and analog watchdog
■ Internal reference voltage measurement
I/Os
■ Up to 28 I/Os on a 32-pin package including 21 high sink outputs
■ Highly robust I/O design, immune against current injection
■ Development support
– Embedded single wire interface module (SWIM) for fast on-chip programming and non intrusive debugging
Unique ID
■ 96-bit key including lot number
LQFP32 7x7 VFQFPN32 5x5