The most popular members of this family are the ATmega644 and the ATmega1284. The others are much less common,
partly because of the electronics "pop culture", which has chosen the ATmega644 to be the big brother of the
Arduino's ATmega328. If you just need I/O, and not a lot of memory, it may be worthwhile to check into the
ATmega164 and ATmega324, although there is a lot to say for standardizing on the ATmega644. For lower power (lower
Vcc) there is the ATmegaXX4PV-10PU, with a Vcc down to 1.8V. All versions of the ATmegaXX4P run at up to 20MHz
with the exception of the ATmegaXX4PV versions, which run at a maximum of 10MHz.
Power Supply vs. Maximum Frequency
The calculator below provides a way to find the maximum operating frequency for any valid power supply voltage
(2.7 to 5.5). Enter the power supply voltage and click "Calculate Max Frequency" to find the ATmegaxx4's specified
maximum clock speed at your Vcc.
Maximum Frequency Calculator for ATmega164/324/644/1284
|I/O Pins ||32|
|ADC Channels ||8|
|RT Counter (w/osc)||1|
|Timers (8-bit) ||2|
|Timers (16-bit) ||1||2|
|PWM (8-bit) ||4|
|PWM (16-bit) ||2|
|Price (1's) ||$5.73||$7.33||$8.38||$8.32|
|Power Consumption (approximate) ||1.125mA/MHz|
|Maximum I/O Current (per pin) ||40mA|
|Maximum I/O Current (all ports) ||100mA(low)/150mA(high)|
|Maximum I/O Current (total) ||200mA (PDIP)|
|Maximum I/O Current (total)||400mA (PDIP/QFP/MLF)|
Link to ATmega164/324/644/1284 datasheet from Atmel's website.
ATmega164/324/644/1284 "Minimal" Circuit Diagram
The circuit below shows a
programming port, reset circuit, and a crystal oscillator. Any or all of these could be left off and the device
would function perfectly well. By default the unit runs from the 1MHz internal RC oscillator.