This page is taken from TODO file in source root. Some points are maybe obsolete or done. This is to check!
LCD subsystem is simlified to
only a 4*20 character type is available
the timing is fixed as described for the 5V-versions
only the 4 bit interface is supported. At start-up the commands are interpreted as if an eight bit interface is available (one write cycle per command). After finishing the initialization switching to the four bit interface is permitted at any time.
follows the rules of your display, not of the LCD character generator.
loadable characters are not supported.
reading of display is not supported.
reading of busy flag does not give the current address in the lower bits.
scrolling not supported.
shift right / left of the display content is not supported.
only one character set is supported - based on your diplay font.
Scope subsystem is an empty frame
Serial Rx/Tx is simplfied to
Waiting at a breakpoint for a GDB user input: the active wait-loop should be replaced by something using less CPU power.