Holtek HT32F1251

The Holtek HT32F1251 is an ARM Cortex-M3 processor - Up to 72 MHz operation frequency - Nested Vectored Interrupt Controller (NVIC) - 24-bit SysTick timer On-chip memory - 8 KB on-chip Flash Memory with Flash Memory Accelerator - 1 KB Flash Option Byte - 2 KB on-chip SRAM - Flexible booting mode supports bootloader Flash Memory Controller - Flash accelerator to obtain maximum efficiency - 32-bit word programming (ISP and IAP) - Flash protection capability to prevent illegal access Power supply, reset, and clocks - Single 3.3 V power supply (2.7 V to 3.6 V) - Built-in 1.8 V LDO regulator for core and peripherals - Supply supervisor (POR, BOD, LVD) - External 4 to 16 MHz crystal oscillator - External 32,768 Hz crystal oscillator - Internal 8 MHz RC oscillator - Internal 32 kHz RC oscillator - On-chip PLL for system clock Power management - 4 power saving modes (Sleep, Deep-Sleep 1, Deep-Sleep 2, Power-Down) - Independent clock gating bits for each peripherals - VBAT battery power supply for RTC and backup registers ADC - 12-bit SAR ADC engine - Up to 1 Msps conversion rate - 8 external analog input channels - 2.7 V ~ 3.6 V conversion range Analog Operational Amplifier/Comparator - 2 x Operational Amplifier or 2 x Comparator function - Supply voltage range: 2.7 V ~ 3.6 V IO ports - Up to 32 GPIOs - Port A and Port B are mapped on 16 ext. interrupts (EXTI) - Almost all IOs are 5 V-tolerant except analog inputs Timers - 2 x 16-bit General-Purpose Timer (GPTM) with input capture or compare output function - 1 x Watchdog timer - 1 x Real Time Clock Communication interfaces - 1 x I2C interface, support both master and slave mode, up to 400 kHz - 1 x SPI interface, support both master and slave mode, up to 18 MHz - 1 x USART interface, up to 4.5 MHz Debug support - Serial Wire Debug Port (SW-DP) - 1-bit asynchronous trace (TRACESWO).