I have a board with a 7-segment display controlled by an AVR. I need to rotate the display's characters in the firmware, so that the display is read correctly when physically rotated 180 degrees.
Currently, the display has an output defined by:
#define SEVEN_SEGMENT_PATTERN_0 0x7B
#define SEVEN_SEGMENT_PATTERN_1 0x09
#define SEVEN_SEGMENT_PATTERN_2 0xB3
#define SEVEN_SEGMENT_PATTERN_3 0x9B
#define SEVEN_SEGMENT_PATTERN_4 0xC9
#define SEVEN_SEGMENT_PATTERN_5 0xDA
#define SEVEN_SEGMENT_PATTERN_6 0xFa
#define SEVEN_SEGMENT_PATTERN_7 0x0B
#define SEVEN_SEGMENT_PATTERN_8 0xFB
#define SEVEN_SEGMENT_PATTERN_9 0xDB
#define SEVEN_SEGMENT_PATTERN_A 0xEB
#define SEVEN_SEGMENT_PATTERN_B 0xF8
#define SEVEN_SEGMENT_PATTERN_C 0x72
#define SEVEN_SEGMENT_PATTERN_D 0xB9
#define SEVEN_SEGMENT_PATTERN_E 0xF2
#define SEVEN_SEGMENT_PATTERN_F 0xE2
#define SEVEN_SEGMENT_PATTERN_G 0xdb
#define SEVEN_SEGMENT_PATTERN_H 0xE9
#define SEVEN_SEGMENT_PATTERN_I 0x09
#define SEVEN_SEGMENT_PATTERN_J 0x19
#define SEVEN_SEGMENT_PATTERN_L 0x70
#define SEVEN_SEGMENT_PATTERN_O 0x7b
#define SEVEN_SEGMENT_PATTERN_P 0xe3
#define SEVEN_SEGMENT_PATTERN_R 0xa0
#define SEVEN_SEGMENT_PATTERN_S 0xda
#define SEVEN_SEGMENT_PATTERN_U 0x79
#define SEVEN_SEGMENT_PATTERN_DOT 0x04
Of course, I could use this to extract the pinout of the display and manually figure out the new definitions for flipped characters. However, this would be time consuming and I'm thinking that there must be a smarter way.
Some would remain the same when flipped, such as SEVEN_SEGMENT_PATTERN_0. Some will be easy to flip if I knew the pinout, such as SEVEN_SEGMENT_PATTERN_1.
Is there some smart algorithm or whatever that can help me calculate the flipped values?
Best Answer
Looks like the pinout is, from most to least significant bit, G F E D C dot A B.
You could write some code along the lines of