Atmel AVR ATMEGA328P-20PU Arduino UNO 

The high-performance Atmel picoPower 8-bit AVR RISC-based microcontroller combines 32KB ISP flash memory with read-while-write capabilities, 1024B EEPROM, 2KB SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible timer/counters with compare modes, internal and external interrupts, serial programmable USART, a byte-oriented 2-wire serial interface, SPI serial port, a 6-channel 10-bit A/D converter (8-channels in TQFP and QFN/MLF packages), programmable watchdog timer with internal oscillator, and five software selectable power saving modes. The device operates between 1.8-5.5 volts.
By executing powerful instructions in a single clock cycle, the device achieves throughputs approaching 1 MIPS per MHz, balancing power consumption and processing speed.
for arduino you need to install bootloader first. 

Key Parameters

Parameter
Value
Flash (Kbytes):

32 Kbytes

Pin Count:

32

Max. Operating Freq. (MHz):

20 MHz

CPU:

8-bit AVR

# of Touch Channels:

16

Hardware QTouch Acquisition:

No

Max I/O Pins:

23

Ext Interrupts:

24

USB Speed:

No

USB Interface:

No