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Difference between revisions of "seven-segment display/representing letters"
(Created page with "{{title|Representing Letters on a Seven-Segment Display}} {| style="float: right; text-align: center; width: 190px;" | <span style="border: 1px solid black; display:inline-tab...") |
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! a !! b !! c !! d !! e !! f !! g | ! a !! b !! c !! d !! e !! f !! g | ||
|- | |- | ||
| − | | A || 1 || 1 || 1 || 0 || 1 || 1 || 1 || 0x77 || 0x77 || {{7seg|A|10}} || rowspan=" | + | | A || 1 || 1 || 1 || 0 || 1 || 1 || 1 || 0x77 || 0x77 || {{7seg|A|10}} || rowspan="23" | [[File:7 segment display labeled.svg|200px]] |
|- | |- | ||
| b || 0 || 0 || 1 || 1 || 1 || 1 || 1 || 0x1F || 0x7C || {{7seg|b|10}} | | b || 0 || 0 || 1 || 1 || 1 || 1 || 1 || 0x1F || 0x7C || {{7seg|b|10}} | ||
|- | |- | ||
| C || 1 || 0 || 0 || 1 || 1 || 1 || 0 || 0x4E || 0x39 || {{7seg|C|10}} | | C || 1 || 0 || 0 || 1 || 1 || 1 || 0 || 0x4E || 0x39 || {{7seg|C|10}} | ||
| + | |- | ||
| + | | c || 0 || 0 || 0 || 1 || 1 || 0 || 1 || 0x0D || 0x58 || {{7seg|c|10}} | ||
|- | |- | ||
| d || 0 || 1 || 1 || 1 || 1 || 0 || 1 || 0x3D || 0x5E || {{7seg|d|10}} | | d || 0 || 1 || 1 || 1 || 1 || 0 || 1 || 0x3D || 0x5E || {{7seg|d|10}} | ||
| Line 28: | Line 30: | ||
|- | |- | ||
| H || 0 || 1 || 1 || 0 || 1 || 1 || 1 || 0x37 || 0x76 || {{7seg|H|10}} | | H || 0 || 1 || 1 || 0 || 1 || 1 || 1 || 0x37 || 0x76 || {{7seg|H|10}} | ||
| + | |- | ||
| + | | h || 0 || 0 || 1 || 0 || 1 || 1 || 1 || 0x17 || 0x74 || {{7seg|h|10}} | ||
|- | |- | ||
| I || 0 || 0 || 0 || 0 || 1 || 1 || 0 || 0x06 || 0x30 || {{7seg|I|10}} | | I || 0 || 0 || 0 || 0 || 1 || 1 || 0 || 0x06 || 0x30 || {{7seg|I|10}} | ||
| Line 55: | Line 59: | ||
| y || 0 || 1 || 1 || 1 || 0 || 1 || 1 || 0x3B || 0x6E || {{7seg|y|10}} | | y || 0 || 1 || 1 || 1 || 0 || 1 || 1 || 0x3B || 0x6E || {{7seg|y|10}} | ||
|} | |} | ||
| + | |||
| + | == Lookup table == | ||
| + | One can decode letters to pins via a simple lookup table. | ||
| + | <source lang="C"> | ||
| + | const unsigned char seven_seg_digits_decode_abcdefg[75]= { | ||
| + | /* 0 1 2 3 4 5 6 7 8 9 : ; */ | ||
| + | 0x7E, 0x30, 0x6D, 0x79, 0x33, 0x5B, 0x5F, 0x70, 0x7F, 0x7B, 0x00, 0x00, | ||
| + | /* < = > ? @ A B C D E F G */ | ||
| + | 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0x00, 0x4E, 0x00, 0x4F, 0x47, 0x5E, | ||
| + | /* H I J K L M N O P Q R S */ | ||
| + | 0x37, 0x06, 0x3C, 0x00, 0x0E, 0x00, 0x00, 0x00, 0x67, 0x00, 0x00, 0x5B, | ||
| + | /* T U V W X Y Z [ \ ] ^ _ */ | ||
| + | 0x00, 0x3E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | ||
| + | /* ` a b c d e f g h i j k */ | ||
| + | 0x00, 0x00, 0x1F, 0x0D, 0x3D, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, | ||
| + | /* l m n o p q r s t u v w */ | ||
| + | 0x00, 0x00, 0x15, 0x1D, 0x00, 0x73, 0x05, 0x00, 0x0F, 0x1C, 0x00, 0x00, | ||
| + | /* x y z */ | ||
| + | 0x00, 0x3B, 0x00 | ||
| + | }; | ||
| + | const unsigned char seven_seg_digits_decode_gfedcba[75]= { | ||
| + | /* 0 1 2 3 4 5 6 7 8 9 : ; */ | ||
| + | 0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F, 0x00, 0x00, | ||
| + | /* < = > ? @ A B C D E F G */ | ||
| + | 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0x00, 0x39, 0x00, 0x79, 0x71, 0x3D, | ||
| + | /* H I J K L M N O P Q R S */ | ||
| + | 0x76, 0x30, 0x1E, 0x00, 0x38, 0x00, 0x00, 0x00, 0x73, 0x00, 0x00, 0x6D, | ||
| + | /* T U V W X Y Z [ \ ] ^ _ */ | ||
| + | 0x00, 0x3E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | ||
| + | /* ` a b c d e f g h i j k */ | ||
| + | 0x00, 0x00, 0x7C, 0x58, 0x5E, 0x00, 0x00, 0x00, 0x74, 0x00, 0x00, 0x00, | ||
| + | /* l m n o p q r s t u v w */ | ||
| + | 0x00, 0x00, 0x54, 0x5C, 0x00, 0x67, 0x50, 0x00, 0x78, 0x1C, 0x00, 0x00, | ||
| + | /* x y z */ | ||
| + | 0x00, 0x6E, 0x00 | ||
| + | }; | ||
| + | |||
| + | /* Invalid letters are mapped to all segments off (0x00). */ | ||
| + | unsigned char decode_7seg(unsigned char chr) | ||
| + | { /* assuming implementation uses ASCII */ | ||
| + | if (chr > (unsigned char)'z') | ||
| + | return 0x00; | ||
| + | return seven_seg_digits_decode_abcdefg[chr - '0']; | ||
| + | /* or seven_seg_digits_decode_gfedcba */ | ||
| + | } | ||
| + | </source> | ||
Revision as of 22:01, 10 November 2015
  
|
| A common method of indicating an error. |
Representing Letters on a Seven-Segment Display, while highly discouraged, have been done mostly in low-end products such as cheap portable media players and many hobby projects. In such places, 7-segment displays were extended to support letters. Those representations varies from implementation to implementation and are not standardized by any standards organization.
Note that some letters such as K (
), M (
), V (
), W (
), X (
), and Z (
) are completely unrecognizable by most people and as such been left out of the table below.
| Digit | 7-Segments | abcdefg | gfedcba | Display | Reference | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| a | b | c | d | e | f | g | |||||
| A | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0x77 | 0x77 |  |
|
| b | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0x1F | 0x7C | 
| |
| C | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 0x4E | 0x39 | 
| |
| c | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0x0D | 0x58 | 
| |
| d | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 0x3D | 0x5E | 
| |
| E | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 0x4F | 0x79 |
| |
| F | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0x47 | 0x71 | 
| |
| G | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 0x5E | 0x3D | 
| |
| H | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 0x37 | 0x76 | 
| |
| h | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 0x17 | 0x74 | 
| |
| I | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0x06 | 0x30 | 
| |
| J | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 0x3C | 0x1E | 
| |
| L | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0x0E | 0x38 | 
| |
| n | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0x15 | 0x54 | 
| |
| o | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 0x1D | 0x5C |
| |
| P | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0x67 | 0x73 | 
| |
| q | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0x73 | 0x67 | 
| |
| r | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0x05 | 0x50 |
| |
| S | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0x5B | 0x6D | 
| |
| t | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 0x0F | 0x78 | 
| |
| U | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0x3E | 0x3E | 
| |
| u | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0x1C | 0x1C | 
| |
| y | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 0x3B | 0x6E | 
| |
Lookup table
One can decode letters to pins via a simple lookup table.
const unsigned char seven_seg_digits_decode_abcdefg[75]= {
/* 0 1 2 3 4 5 6 7 8 9 : ; */
0x7E, 0x30, 0x6D, 0x79, 0x33, 0x5B, 0x5F, 0x70, 0x7F, 0x7B, 0x00, 0x00,
/* < = > ? @ A B C D E F G */
0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0x00, 0x4E, 0x00, 0x4F, 0x47, 0x5E,
/* H I J K L M N O P Q R S */
0x37, 0x06, 0x3C, 0x00, 0x0E, 0x00, 0x00, 0x00, 0x67, 0x00, 0x00, 0x5B,
/* T U V W X Y Z [ \ ] ^ _ */
0x00, 0x3E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
/* ` a b c d e f g h i j k */
0x00, 0x00, 0x1F, 0x0D, 0x3D, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00,
/* l m n o p q r s t u v w */
0x00, 0x00, 0x15, 0x1D, 0x00, 0x73, 0x05, 0x00, 0x0F, 0x1C, 0x00, 0x00,
/* x y z */
0x00, 0x3B, 0x00
};
const unsigned char seven_seg_digits_decode_gfedcba[75]= {
/* 0 1 2 3 4 5 6 7 8 9 : ; */
0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F, 0x00, 0x00,
/* < = > ? @ A B C D E F G */
0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0x00, 0x39, 0x00, 0x79, 0x71, 0x3D,
/* H I J K L M N O P Q R S */
0x76, 0x30, 0x1E, 0x00, 0x38, 0x00, 0x00, 0x00, 0x73, 0x00, 0x00, 0x6D,
/* T U V W X Y Z [ \ ] ^ _ */
0x00, 0x3E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
/* ` a b c d e f g h i j k */
0x00, 0x00, 0x7C, 0x58, 0x5E, 0x00, 0x00, 0x00, 0x74, 0x00, 0x00, 0x00,
/* l m n o p q r s t u v w */
0x00, 0x00, 0x54, 0x5C, 0x00, 0x67, 0x50, 0x00, 0x78, 0x1C, 0x00, 0x00,
/* x y z */
0x00, 0x6E, 0x00
};
/* Invalid letters are mapped to all segments off (0x00). */
unsigned char decode_7seg(unsigned char chr)
{ /* assuming implementation uses ASCII */
if (chr > (unsigned char)'z')
return 0x00;
return seven_seg_digits_decode_abcdefg[chr - '0'];
/* or seven_seg_digits_decode_gfedcba */
}