Types of AVR’s

AVRs are generally classified into four broad groups:
• tinyAVR -- the ATtiny series
o 8-32-pin package
o 1-8 kB program memory
o Limited peripheral set
• megaAVR -- the ATmega series
o 28-100-pin package
o 4-256 kB program memory
o Extended instruction set (Multiply instructions and instructions for handling larger program memories)
o Extensive peripheral set
• XMEGA -- the ATxmega series
o 44-64-100-pin package (A4, A3, A1)
o 16-384 kB program memory
o Extended performance features, such as DMA, "Event System", and cryptography support.
o Extensive peripheral set with DACs
• Application specific AVR
o megaAVRs with special features not found on the other members of the AVR family, such as USB controller, LCD controller, advanced PWM, CAN etc.
o FPSLIC (Field Programmable System Level Integrated Circuit), an AVR core on-die with an FPGA. The FPSLIC uses SRAM for the AVR program code, unlike all other AVRs. Partly due to the relative speed difference between SRAM and flash, the AVR core in the FPSLIC can run at up to 50MHz.