Thorkild Pedersen
/
morsemsg
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morsemsg.cpp@0:023075f6fafd, 2010-10-26 (annotated)
- Committer:
- tfind
- Date:
- Tue Oct 26 23:13:58 2010 +0000
- Revision:
- 0:023075f6fafd
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| tfind | 0:023075f6fafd | 1 | #include "mbed.h" |
| tfind | 0:023075f6fafd | 2 | |
| tfind | 0:023075f6fafd | 3 | DigitalOut myled(LED1); |
| tfind | 0:023075f6fafd | 4 | |
| tfind | 0:023075f6fafd | 5 | /// Send the string message in morse code on 'myled |
| tfind | 0:023075f6fafd | 6 | void morse_string(char *msg); |
| tfind | 0:023075f6fafd | 7 | |
| tfind | 0:023075f6fafd | 8 | // Timing constants for morse code generation |
| tfind | 0:023075f6fafd | 9 | #define TDOT 0.2 |
| tfind | 0:023075f6fafd | 10 | #define TDASH (3*TDOT) |
| tfind | 0:023075f6fafd | 11 | #define TSPLIT (1*TDOT) |
| tfind | 0:023075f6fafd | 12 | #define TSPACE (3*TDASH) |
| tfind | 0:023075f6fafd | 13 | |
| tfind | 0:023075f6fafd | 14 | int main() { |
| tfind | 0:023075f6fafd | 15 | while (1) { |
| tfind | 0:023075f6fafd | 16 | morse_string("hello world"); |
| tfind | 0:023075f6fafd | 17 | wait(2*TSPACE); |
| tfind | 0:023075f6fafd | 18 | } |
| tfind | 0:023075f6fafd | 19 | } |
| tfind | 0:023075f6fafd | 20 | |
| tfind | 0:023075f6fafd | 21 | /// Table with morse code bit-patterns. |
| tfind | 0:023075f6fafd | 22 | /// Each symbols dot/dash sequence is stored starting at bit 0 where |
| tfind | 0:023075f6fafd | 23 | /// a set bit encodes a dash and cleared bit a dot. The sequence is terminated by a set trailing bit- |
| tfind | 0:023075f6fafd | 24 | unsigned char alphabet[] = { |
| tfind | 0:023075f6fafd | 25 | 0x06, // .- a |
| tfind | 0:023075f6fafd | 26 | 0x11, // -... b |
| tfind | 0:023075f6fafd | 27 | 0x15, // -.-. c |
| tfind | 0:023075f6fafd | 28 | 0x09, // -.. d |
| tfind | 0:023075f6fafd | 29 | 0x02, // . e |
| tfind | 0:023075f6fafd | 30 | 0x14, // ..-. f |
| tfind | 0:023075f6fafd | 31 | 0x0b, // --. g |
| tfind | 0:023075f6fafd | 32 | 0x10, // .... h |
| tfind | 0:023075f6fafd | 33 | 0x08, // .. i |
| tfind | 0:023075f6fafd | 34 | 0x1e, // .--- j |
| tfind | 0:023075f6fafd | 35 | 0x0d, // -.- k |
| tfind | 0:023075f6fafd | 36 | 0x12, // .-.. l |
| tfind | 0:023075f6fafd | 37 | 0x07, // -- m |
| tfind | 0:023075f6fafd | 38 | 0x05, // -. n |
| tfind | 0:023075f6fafd | 39 | 0x0F, // --- o |
| tfind | 0:023075f6fafd | 40 | 0x16, // .--. p |
| tfind | 0:023075f6fafd | 41 | 0x1b, // --.- q |
| tfind | 0:023075f6fafd | 42 | 0x0a, // .-. r |
| tfind | 0:023075f6fafd | 43 | 0x08, // ... s |
| tfind | 0:023075f6fafd | 44 | 0x03, // - t |
| tfind | 0:023075f6fafd | 45 | 0x0c, // ..- u |
| tfind | 0:023075f6fafd | 46 | 0x18, // ...- v |
| tfind | 0:023075f6fafd | 47 | 0x0e, // .-- w |
| tfind | 0:023075f6fafd | 48 | 0x19, // -..- x |
| tfind | 0:023075f6fafd | 49 | 0x1d, // -.-- y |
| tfind | 0:023075f6fafd | 50 | 0x13, // --.. z |
| tfind | 0:023075f6fafd | 51 | 0x3f, // ----- 0 |
| tfind | 0:023075f6fafd | 52 | 0x3e, // .---- 1 |
| tfind | 0:023075f6fafd | 53 | 0x3c, // ..--- 2 |
| tfind | 0:023075f6fafd | 54 | 0x38, // ...-- 3 |
| tfind | 0:023075f6fafd | 55 | 0x30, // ....- 4 |
| tfind | 0:023075f6fafd | 56 | 0x20, // ..... 5 |
| tfind | 0:023075f6fafd | 57 | 0x21, // -.... 6 |
| tfind | 0:023075f6fafd | 58 | 0x23, // --... 7 |
| tfind | 0:023075f6fafd | 59 | 0x27, // ---.. 8 |
| tfind | 0:023075f6fafd | 60 | 0x2f, // ----. 9 |
| tfind | 0:023075f6fafd | 61 | 0x73, // --..-- , |
| tfind | 0:023075f6fafd | 62 | 0x6a, // .-.-.- . |
| tfind | 0:023075f6fafd | 63 | 0x00 |
| tfind | 0:023075f6fafd | 64 | }; |
| tfind | 0:023075f6fafd | 65 | |
| tfind | 0:023075f6fafd | 66 | /// Convert a character to a morse-code bit pattern. |
| tfind | 0:023075f6fafd | 67 | unsigned char getCode(char symbol) { |
| tfind | 0:023075f6fafd | 68 | if (symbol >= 'a' && symbol <= 'z') return alphabet[symbol-'a']; |
| tfind | 0:023075f6fafd | 69 | else if (symbol >= '0' && symbol <= '9') return alphabet[symbol-'0'+26]; |
| tfind | 0:023075f6fafd | 70 | else if (symbol == '.') return alphabet[37]; |
| tfind | 0:023075f6fafd | 71 | else if (symbol == ',') return alphabet[36]; |
| tfind | 0:023075f6fafd | 72 | else return 0; |
| tfind | 0:023075f6fafd | 73 | } |
| tfind | 0:023075f6fafd | 74 | |
| tfind | 0:023075f6fafd | 75 | /// Pattern of current symbol being send. |
| tfind | 0:023075f6fafd | 76 | unsigned char morse_pattern = 0; |
| tfind | 0:023075f6fafd | 77 | |
| tfind | 0:023075f6fafd | 78 | /// Set the symbol to be morsed. |
| tfind | 0:023075f6fafd | 79 | /// Returns bit pattern of morse code or zero if symbol not found (e.g. for a space) |
| tfind | 0:023075f6fafd | 80 | int morse_setsymbol(char symbol) { |
| tfind | 0:023075f6fafd | 81 | return morse_pattern = getCode(symbol); |
| tfind | 0:023075f6fafd | 82 | } |
| tfind | 0:023075f6fafd | 83 | |
| tfind | 0:023075f6fafd | 84 | /// Generate next dot/dash to transmit |
| tfind | 0:023075f6fafd | 85 | /// Returns 0 for dot, 1 for dash and -1 for finished |
| tfind | 0:023075f6fafd | 86 | int morse_next() { |
| tfind | 0:023075f6fafd | 87 | int retval = (morse_pattern & 1) ? 1 : 0; |
| tfind | 0:023075f6fafd | 88 | morse_pattern >>= 1; |
| tfind | 0:023075f6fafd | 89 | if (! morse_pattern) retval = -1; |
| tfind | 0:023075f6fafd | 90 | return retval; |
| tfind | 0:023075f6fafd | 91 | } |
| tfind | 0:023075f6fafd | 92 | |
| tfind | 0:023075f6fafd | 93 | void morse_string(char *msg) { |
| tfind | 0:023075f6fafd | 94 | int x; |
| tfind | 0:023075f6fafd | 95 | for (; *msg; msg++) { |
| tfind | 0:023075f6fafd | 96 | if (!morse_setsymbol(*msg)) { |
| tfind | 0:023075f6fafd | 97 | wait(TSPACE); |
| tfind | 0:023075f6fafd | 98 | continue; |
| tfind | 0:023075f6fafd | 99 | } |
| tfind | 0:023075f6fafd | 100 | for (x=morse_next(); x != -1; x=morse_next()) { |
| tfind | 0:023075f6fafd | 101 | myled = 1; |
| tfind | 0:023075f6fafd | 102 | wait(x ? TDASH : TDOT); |
| tfind | 0:023075f6fafd | 103 | myled = 0; |
| tfind | 0:023075f6fafd | 104 | wait(TSPLIT); |
| tfind | 0:023075f6fafd | 105 | } |
| tfind | 0:023075f6fafd | 106 | wait(TDASH); |
| tfind | 0:023075f6fafd | 107 | } |
| tfind | 0:023075f6fafd | 108 | } |