The hwtest is a small test to verify the correct behavior of the board specific operations that control the graphic dot matrix. It only uses the _gdm_hw_xxx operations (see Hardware Low Level Operation for Graphic Display Manager).
If the GDM12864 is connected and has proper board specific operations, the test shows crossing lines on the complete display. These crossing lines are progressively erased by a 8x8 square that moves from left to right and top to bottom. Once the display is erased, the crossing lines are drawn again.
Source file: hwtest.c