Design question - why Arduino migrated to ATMega168 series ?

Hello, I've not use Arduino yet, so my question may be seem strange.

I've read that some previous version of Arduinos made use of ATMega8 uC (Ordinarily I also use this uC). Why did someone take a decision to use ATMega168 uC ? Is it caused by memory, max.freq and interrupts number advantage of ATMega168 ? Or ATMega8 just considered as something old ?

Thank you

If you look at the datasheets, there are a whole family of 28 pin DIPs in the ATMegaxx8 series, ending with the '328. Difference is just memory size increases basically.

Pin compatibility.

When the ATmega8 first started (about ten years ago or so), the higher memory size was the ATmega16 and 32 which were available in 40 pin DIP package. Moving on to those chips would mean that they had to create a new board from scratch.

Instead, ATMEL launched the ATmega644 and 1284 and CrossRoads did the rest as you can see in his signature. ;)

Yup, thanks for that!

Eagle says "Mega8-P 8 Kbytes FLASH, 1 kbytes SRAM, 512 bytes EEPROM, USART, 4-channel 10 bit ADC, 2-channel 8 bit ADC and is Pin compatible with Atmega48, ATMega88, ATMega168" (and we know the ATMega328 as well)

So Atmel added more memory to the 8 as an upgrade path apparantly? No ATMega648. Yet?

The 648 with a 28 pin DIP package would be awesome. :)

Can do a lot with a 1284 tho too, careful layout makes for a board not much bigger than a 28 pin DIP board.
For example, here’s a 40 pin DIP with 14pin DIP op amp.