ATmega328/P - Modes of Operation

Is it possible to place the ATmega328/P microcontroller into kernel mode versus user mode?

Solution

No. The 8-bit AVR core does not have any privileged modes or instructions. Nor does it have a MPU so there is no kernel vs user mode distinction.

Which Arduino Uno pin corresponds to TCNT0?
Multiple programs on AVR atmega
Arduino LED blink 3 time without reasons
Arduino UNO Hangs on USART0 RX ISR
[Arduino][Register manipulation] How to make your own Serial.print() with registers?
Multiply two 8 bit number that gives 16bit number as result, with 8bit register and only add instruction
AVR Atmega32a USART library isn't working
Why isn't my polling routine working when I poll on interrupt and works when I do on main routine
Why are functions executed in the order they are defined and not in the order they are called from the int main() in avr-c?
Why am I getting this error in proteus: "Invalid opcode 0xFFFF at PC=0x0008"
Using timer0 to measure execution time on atmega2560
Port G ATmega128 AVR Assembly
TCC timer stops apparently without reason on ATXMEGA16E5
How to verify the TIMER2 overflow frequency in atmega328p?
How can I read correctly integer coming in serial port?
Handling several AVR Interrupt Vectors
Defining ISR crashes ATmega328p
ATMEGA4809 UART bootloader block gets corrupted randomly
Why does this AVR code for ATMega128 behave the way it does?
Connecting 6116 to ATMega128
Weird behavior of ATMega4809's hardware timer
How can a UART signal from a ATMEGA8535 be 200x slower than that from a Arduino with a ATMEGA328?
Transmission and receiving of data through serial(in C)
How do I detect a button release?
How do I assign a value to a variable once?
AVR - MCP4921, custom sinewave frequency
atmega32u4 Failed to enter programming mode
How to detect how long a button was pressed in Arduino?
Problem with serial communication between Arduino Mega2560 and ESP32
BAD USB Atmega32u4 - Problem with performing various activities on one USB