Mercurial > templog
annotate simple_ds18b20.c @ 124:24e343a3ef93
update sensors config
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 10 Oct 2012 22:50:02 +0800 |
parents | 295a4b875677 |
children |
rev | line source |
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12 | 1 // Matt Johnston 2012 |
2 // Based on ds18x20.c by Martin Thomas, in turn based on code by | |
3 // Peter // Dannegger and others. | |
4 // | |
5 #include <stdio.h> | |
6 #include <avr/pgmspace.h> | |
7 | |
8 #include "ds18x20.h" | |
9 #include "onewire.h" | |
10 #include "crc8.h" | |
11 | |
12 #include "simple_ds18b20.h" | |
13 | |
14 uint8_t | |
15 simple_ds18b20_start_meas(uint8_t id[]) | |
16 { | |
17 uint8_t ret; | |
18 | |
19 ow_reset(); | |
20 if( ow_input_pin_state() ) { // only send if bus is "idle" = high | |
21 ow_command_with_parasite_enable(DS18X20_CONVERT_T, id); | |
22 ret = DS18X20_OK; | |
23 } | |
24 else { | |
25 ret = DS18X20_START_FAIL; | |
26 } | |
27 | |
28 return ret; | |
29 } | |
30 | |
31 static uint8_t | |
32 read_scratchpad( uint8_t id[], uint8_t sp[], uint8_t n ) | |
33 { | |
34 uint8_t i; | |
35 uint8_t ret; | |
36 | |
37 ow_command( DS18X20_READ, id ); | |
38 for ( i = 0; i < n; i++ ) { | |
39 sp[i] = ow_byte_rd(); | |
40 } | |
41 if ( crc8( &sp[0], DS18X20_SP_SIZE ) ) { | |
42 ret = DS18X20_ERROR_CRC; | |
43 } else { | |
44 ret = DS18X20_OK; | |
45 } | |
46 | |
47 return ret; | |
48 } | |
49 | |
115 | 50 int16_t |
51 ds18b20_raw16_to_decicelsius(uint16_t measure) | |
12 | 52 { |
53 uint8_t negative; | |
54 int16_t decicelsius; | |
55 uint16_t fract; | |
56 | |
57 // check for negative | |
58 if ( measure & 0x8000 ) { | |
59 negative = 1; // mark negative | |
60 measure ^= 0xffff; // convert to positive => (twos complement)++ | |
61 measure++; | |
62 } | |
63 else { | |
64 negative = 0; | |
65 } | |
66 | |
67 decicelsius = (measure >> 4); | |
68 decicelsius *= 10; | |
69 | |
70 // decicelsius += ((measure & 0x000F) * 640 + 512) / 1024; | |
71 // 625/1000 = 640/1024 | |
72 fract = ( measure & 0x000F ) * 640; | |
73 if ( !negative ) { | |
74 fract += 512; | |
75 } | |
76 fract /= 1024; | |
77 decicelsius += fract; | |
78 | |
79 if ( negative ) { | |
80 decicelsius = -decicelsius; | |
81 } | |
82 | |
120 | 83 if ( decicelsius == 850 || decicelsius < -550 || decicelsius > 1250 ) { |
12 | 84 return DS18X20_INVALID_DECICELSIUS; |
85 } else { | |
86 return decicelsius; | |
87 } | |
88 } | |
89 | |
90 uint8_t | |
91 simple_ds18b20_read_decicelsius( uint8_t id[], int16_t *decicelsius ) | |
92 { | |
115 | 93 uint16_t reading; |
12 | 94 uint8_t ret; |
115 | 95 |
96 ret = simple_ds18b20_read_raw(id, &reading); | |
97 if (ret == DS18X20_OK) | |
98 { | |
99 *decicelsius = ds18b20_raw16_to_decicelsius(reading); | |
100 } | |
101 return ret; | |
12 | 102 } |
103 | |
75
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104 uint8_t |
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105 simple_ds18b20_read_raw( uint8_t id[], uint16_t *reading ) |
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106 { |
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107 uint8_t sp[DS18X20_SP_SIZE]; |
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108 uint8_t ret; |
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109 |
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110 if (id) |
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111 { |
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112 ow_reset(); |
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113 } |
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114 ret = read_scratchpad( id, sp, DS18X20_SP_SIZE ); |
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115 if ( ret == DS18X20_OK ) { |
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116 *reading = sp[0] | (sp[1] << 8); |
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117 } |
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118 return ret; |
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119 } |
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120 |
12 | 121 static void |
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122 printhex_nibble(const unsigned char b, FILE *stream) |
12 | 123 { |
124 unsigned char c = b & 0x0f; | |
125 if ( c > 9 ) { | |
126 c += 'A'-10; | |
127 } | |
128 else { | |
129 c += '0'; | |
130 } | |
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131 fputc(c, stream); |
12 | 132 } |
133 | |
134 void | |
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135 printhex_byte(const unsigned char b, FILE *stream) |
12 | 136 { |
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137 printhex_nibble( b >> 4, stream); |
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138 printhex_nibble( b, stream); |
12 | 139 } |
140 | |
141 void | |
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142 printhex(uint8_t *id, uint8_t n, FILE *stream) |
12 | 143 { |
144 for (uint8_t i = 0; i < n; i++) | |
145 { | |
146 if (i > 0) | |
147 { | |
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148 fputc(' ', stream); |
12 | 149 } |
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150 printhex_byte(id[i], stream); |
12 | 151 } |
152 } | |
153 | |
154 | |
155 uint8_t | |
156 simple_ds18b20_read_all() | |
157 { | |
158 uint8_t id[OW_ROMCODE_SIZE]; | |
159 for( uint8_t diff = OW_SEARCH_FIRST; diff != OW_LAST_DEVICE; ) | |
160 { | |
161 diff = ow_rom_search( diff, &id[0] ); | |
162 | |
163 if( diff == OW_PRESENCE_ERR ) { | |
164 printf_P( PSTR("No Sensor found\r") ); | |
165 return OW_PRESENCE_ERR; // <--- early exit! | |
166 } | |
167 | |
168 if( diff == OW_DATA_ERR ) { | |
169 printf_P( PSTR("Bus Error\r") ); | |
170 return OW_DATA_ERR; // <--- early exit! | |
171 } | |
172 | |
173 int16_t decicelsius; | |
174 uint8_t ret = simple_ds18b20_read_decicelsius(NULL, &decicelsius); | |
175 if (ret != DS18X20_OK) | |
176 { | |
177 printf_P(PSTR("Failed reading\r")); | |
178 return OW_DATA_ERR; | |
179 } | |
180 | |
181 printf_P(PSTR("DS18B20 %d: "), diff); | |
182 if (crc8(id, OW_ROMCODE_SIZE)) | |
183 { | |
184 printf_P(PSTR("CRC fail")); | |
185 } | |
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186 printhex(id, OW_ROMCODE_SIZE, stdout); |
12 | 187 printf_P(PSTR(" %d.%d ºC\n"), decicelsius/10, decicelsius % 10); |
188 } | |
189 printf_P(PSTR("Done sensors\n")); | |
190 return DS18X20_OK; | |
191 } | |
192 |