It also explains the difference between Arduino and AVR microcontrollers in general and how ATmega328 and ATmega2560 microcontrollers relate to Arduino Uno and Arduino MEGA boards. Difference Between Arduino and ATmega328 AVR. In short an ATmega328 is a microcontroller chip found on Arduino Uno boards.

• Arduino Uno Mega 2560 R3
• Arduino Uno Vs Mega 2560 X 1440

Yeah i am using them right now but i need some more power so i decided make another shield using
LV8727 driver

DATA
Output on-resistance (upper side : 0.25Ω ; lower side : 0.15Ω ; total of upper and lower : 0.4Ω ; Ta = 25°C, IO = 4.0A)

Low Consumption, High Efficiency
Half, 1/8, 1/16, 1/32, 1/64, 1/128, 1/10, 1/20 Step are selectable.

Various Step Adjustment Available
Over current protection circuit.

Over current protection
Thermal shutdown circuit.

Thermal protection
Current saving function

Low Consumption
Output Current : 4A

Large motor current
Single-channel PWM current control stepping motor driver.

BiCDMOS process IC.

Advance the excitation step with the only step signal input.

Arduino Uno Mega 2560 R3

Available forward reverse control.

Input pull down resistance.

With reset pin and enable pin.

it basicly has every thing any driver should have just the microstepping is kinda weird ..
and no full step .

I managed also yesterday to send some data to grbl via atmega8 so i probably put also some manual moving functionality in to it .

Arduino Uno Vs Mega 2560 X 1440

I may also use the A4989 from allegro with external fets if the lv8727 steping modes does not work for all machines.. I need to research that.