I'm getting started with the RePaper Development Board from Adafruit (https://learn.adafruit.com/repaper-eink-development-board/overview) and am confused while reviewing their demo code. After reading about PROGMEM and #define I am unsure on what seems like conflicting or useless use of these keywords. The code is as follows:
PROGMEM const #define unsigned #define char uint8_t #include IMAGE_1_FILE #undef char #undef unsigned
What is going on here? Does the IDE interpret multiple lines at once? Are we assigning all const types to PROGMEM? And making any unsigned types use the #define methodology?
Also what does undef do (did not see a reference)? Does the "#undef unsigned" line conflict with the "#define unsigned" line?
Why would we assign a type of memory space to variable types without variables?