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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 74 | arune | 1 | /************************************************************************/ |
| 2 | /* */ |
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| 3 | /* Access Dallas 1-Wire Device with ATMEL AVRs */ |
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| 4 | /* */ |
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| 5 | /* Author: Peter Dannegger */ |
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| 6 | /* danni@specs.de */ |
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| 7 | /* */ |
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| 8 | /* modified by Martin Thomas <eversmith@heizung-thomas.de> 9/2004 */ |
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| 9 | /************************************************************************/ |
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| 10 | |||
| 11 | #include <avr/io.h> |
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| 12 | #include <avr/interrupt.h> |
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| 13 | |||
| 14 | #include "delay.h" |
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| 15 | #include "onewire.h" |
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| 16 | |||
| 17 | #ifdef OW_ONE_BUS |
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| 18 | |||
| 19 | #define OW_GET_IN() ( OW_IN & (1<<OW_PIN)) |
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| 20 | #define OW_OUT_LOW() ( OW_OUT &= (~(1 << OW_PIN)) ) |
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| 21 | #define OW_OUT_HIGH() ( OW_OUT |= (1 << OW_PIN) ) |
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| 22 | #define OW_DIR_IN() ( OW_DDR &= (~(1 << OW_PIN )) ) |
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| 23 | #define OW_DIR_OUT() ( OW_DDR |= (1 << OW_PIN) ) |
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| 24 | |||
| 25 | #else |
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| 26 | |||
| 27 | /* set bus-config with ow_set_bus() */ |
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| 28 | uint8_t OW_PIN_MASK; |
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| 29 | volatile uint8_t* OW_IN; |
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| 30 | volatile uint8_t* OW_OUT; |
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| 31 | volatile uint8_t* OW_DDR; |
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| 32 | |||
| 33 | #define OW_GET_IN() ( *OW_IN & OW_PIN_MASK ) |
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| 34 | #define OW_OUT_LOW() ( *OW_OUT &= (uint8_t) ~OW_PIN_MASK ) |
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| 35 | #define OW_OUT_HIGH() ( *OW_OUT |= (uint8_t) OW_PIN_MASK ) |
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| 36 | #define OW_DIR_IN() ( *OW_DDR &= (uint8_t) ~OW_PIN_MASK ) |
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| 37 | #define OW_DIR_OUT() ( *OW_DDR |= (uint8_t) OW_PIN_MASK ) |
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| 38 | //#define OW_PIN2 PD6 |
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| 39 | //#define OW_DIR_IN2() ( *OW_DDR &= ~(1 << OW_PIN2 ) ) |
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| 40 | |||
| 41 | void ow_set_bus(volatile uint8_t* in, |
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| 42 | volatile uint8_t* out, |
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| 43 | volatile uint8_t* ddr, |
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| 44 | uint8_t pin) |
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| 45 | { |
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| 46 | OW_DDR=ddr; |
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| 47 | OW_OUT=out; |
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| 48 | OW_IN=in; |
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| 49 | OW_PIN_MASK=(1<<pin); |
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| 50 | ow_reset(); |
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| 51 | } |
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| 52 | |||
| 53 | #endif |
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| 54 | |||
| 55 | uint8_t ow_input_pin_state() |
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| 56 | { |
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| 57 | return OW_GET_IN(); |
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| 58 | } |
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| 59 | |||
| 60 | void ow_parasite_enable(void) |
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| 61 | { |
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| 62 | OW_OUT_HIGH(); |
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| 63 | OW_DIR_OUT(); |
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| 64 | } |
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| 65 | |||
| 66 | void ow_parasite_disable(void) |
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| 67 | { |
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| 68 | OW_OUT_LOW(); |
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| 69 | OW_DIR_IN(); |
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| 70 | } |
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| 71 | |||
| 72 | uint8_t ow_reset(void) |
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| 73 | { |
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| 74 | uint8_t err; |
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| 75 | uint8_t sreg; |
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| 76 | |||
| 77 | OW_OUT_LOW(); // disable internal pull-up (maybe on from parasite) |
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| 78 | OW_DIR_OUT(); // pull OW-Pin low for 480us |
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| 79 | |||
| 80 | delay_us(480); |
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| 81 | |||
| 82 | sreg=SREG; |
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| 83 | cli(); |
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| 84 | |||
| 85 | // set Pin as input - wait for clients to pull low |
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| 86 | OW_DIR_IN(); // input |
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| 87 | |||
| 88 | delay_us(66); |
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| 89 | err = OW_GET_IN(); // no presence detect |
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| 90 | // nobody pulled to low, still high |
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| 91 | |||
| 92 | SREG=sreg; // sei() |
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| 93 | |||
| 94 | // after a delay the clients should release the line |
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| 95 | // and input-pin gets back to high due to pull-up-resistor |
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| 96 | delay_us(480-66); |
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| 97 | if( OW_GET_IN() == 0 ) // short circuit |
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| 98 | err = 1; |
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| 99 | |||
| 100 | return err; |
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| 101 | } |
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| 102 | |||
| 103 | /* Timing issue when using runtime-bus-selection (!OW_ONE_BUS): |
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| 104 | The master should sample at the end of the 15-slot after initiating |
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| 105 | the read-time-slot. The variable bus-settings need more |
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| 106 | cycles than the constant ones so the delays had to be shortened |
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| 107 | to achive a 15uS overall delay |
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| 108 | Setting/clearing a bit in I/O Register needs 1 cyle in OW_ONE_BUS |
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| 109 | but around 14 cyles in configureable bus (us-Delay is 4 cyles per uS) */ |
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| 110 | uint8_t ow_bit_io( uint8_t b ) |
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| 111 | { |
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| 112 | uint8_t sreg; |
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| 113 | |||
| 114 | sreg=SREG; |
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| 115 | cli(); |
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| 116 | |||
| 117 | OW_DIR_OUT(); // drive bus low |
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| 118 | |||
| 119 | delay_us(1); // Recovery-Time wuffwuff was 1 |
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| 120 | if ( b ) OW_DIR_IN(); // if bit is 1 set bus high (by ext. pull-up) |
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| 121 | |||
| 122 | // wuffwuff delay was 15uS-1 see comment above |
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| 123 | delay_us(15-1-OW_CONF_DELAYOFFSET); |
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| 124 | |||
| 125 | if( OW_GET_IN() == 0 ) b = 0; // sample at end of read-timeslot |
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| 126 | |||
| 127 | delay_us(60-15); |
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| 128 | OW_DIR_IN(); |
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| 129 | |||
| 130 | SREG=sreg; // sei(); |
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| 131 | |||
| 132 | return b; |
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| 133 | } |
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| 134 | |||
| 135 | |||
| 136 | uint8_t ow_byte_wr( uint8_t b ) |
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| 137 | { |
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| 138 | uint8_t i = 8, j; |
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| 139 | |||
| 140 | do { |
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| 141 | j = ow_bit_io( b & 1 ); |
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| 142 | b >>= 1; |
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| 143 | if( j ) b |= 0x80; |
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| 144 | } while( --i ); |
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| 145 | |||
| 146 | return b; |
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| 147 | } |
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| 148 | |||
| 149 | |||
| 150 | uint8_t ow_byte_rd( void ) |
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| 151 | { |
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| 152 | // read by sending 0xff (a dontcare?) |
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| 153 | return ow_byte_wr( 0xFF ); |
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| 154 | } |
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| 155 | |||
| 156 | |||
| 157 | uint8_t ow_rom_search( uint8_t diff, uint8_t *id ) |
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| 158 | { |
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| 159 | uint8_t i, j, next_diff; |
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| 160 | uint8_t b; |
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| 161 | |||
| 162 | if( ow_reset() ) return OW_PRESENCE_ERR; // error, no device found |
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| 163 | |||
| 164 | ow_byte_wr( OW_SEARCH_ROM ); // ROM search command |
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| 165 | next_diff = OW_LAST_DEVICE; // unchanged on last device |
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| 166 | |||
| 167 | i = OW_ROMCODE_SIZE * 8; // 8 bytes |
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| 168 | |||
| 169 | do { |
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| 170 | j = 8; // 8 bits |
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| 171 | do { |
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| 172 | b = ow_bit_io( 1 ); // read bit |
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| 173 | if( ow_bit_io( 1 ) ) { // read complement bit |
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| 174 | if( b ) // 11 |
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| 175 | return OW_DATA_ERR; // data error |
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| 176 | } |
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| 177 | else { |
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| 178 | if( !b ) { // 00 = 2 devices |
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| 179 | if( diff > i || ((*id & 1) && diff != i) ) { |
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| 180 | b = 1; // now 1 |
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| 181 | next_diff = i; // next pass 0 |
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| 182 | } |
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| 183 | } |
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| 184 | } |
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| 185 | ow_bit_io( b ); // write bit |
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| 186 | *id >>= 1; |
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| 187 | if( b ) *id |= 0x80; // store bit |
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| 188 | |||
| 189 | i--; |
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| 190 | |||
| 191 | } while( --j ); |
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| 192 | |||
| 193 | id++; // next byte |
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| 194 | |||
| 195 | } while( i ); |
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| 196 | |||
| 197 | return next_diff; // to continue search |
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| 198 | } |
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| 199 | |||
| 200 | |||
| 201 | void ow_command( uint8_t command, uint8_t *id ) |
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| 202 | { |
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| 203 | uint8_t i; |
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| 204 | |||
| 205 | ow_reset(); |
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| 206 | |||
| 207 | if( id ) { |
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| 208 | ow_byte_wr( OW_MATCH_ROM ); // to a single device |
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| 209 | i = OW_ROMCODE_SIZE; |
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| 210 | do { |
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| 211 | ow_byte_wr( *id ); |
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| 212 | id++; |
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| 213 | } while( --i ); |
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| 214 | } |
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| 215 | else { |
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| 216 | ow_byte_wr( OW_SKIP_ROM ); // to all devices |
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| 217 | } |
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| 218 | |||
| 219 | ow_byte_wr( command ); |
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| 220 | } |