assembler code that reads a byte of data stored in a specified address(PROGMEM area).
The _LPM_enhanced_() is defined in hardware/tools/avr/avr/include/avr/pgmspace.h as below.
The lpm, short for Load Program Memory, is a instruction that reads a byte of data from PROGMEM area. It substitue a data at addr for __result, then returns the __result.
May 15, 2021