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PO1wire problem in detail
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copied!<p>I have defined these functions below, and when I ask Device_ID function for example of the family code, I only get FF (should be 28), acctually I get both the family code, 48-bit serial, and the crc 8 bit to be all "ones". It seems like the detect slave device function works as it should.... If i connect the slave he say's I am here, and if i take it away... no device present. I also have a 5kohm pull-up at the 1wire.</p> <p>And I dont have a clue why my Device_ID dont work, so my question is why doesnt it work!? can u see anything wrong within this code (Im using a PIC 18F87J50 and one DS18B20):</p> <p>My statement in Main:</p> <pre><code> OSCTUNEbits.PLLEN = 1; Init_Registers(); Init_Settings(); Init_Ports(); Init_Glcd(); Detect_Slave_Device(); Device_ID( 0x33 ); </code></pre> <p>Used functions:</p> <pre><code> void Detect_Slave_Device(void){ uint8_t value; OW_reset_pulse(); if (OW_reset_pulse()) { Display_Cls(); Display_StringAt("No Device Present!",5,6); Delay_1sec(); Delay_1sec(); } else { Display_Cls(); Display_StringAt("Device Present!",5,6); Delay_1sec(); Delay_1sec(); }} </code></pre> <hr> <pre><code> uint8_t OW_reset_pulse(void){ uint8_t presence_detect; drive_OW_low(); // Drive the bus low Delay_us(200); // Delay at least 480 microsecond (us) Delay_us(200); Delay_us(85); drive_OW_high (); // Release the bus // Here should the client drive low Delay_us(50); // Delay 50 microsecond (us) presence_detect = read_OW(); // Sample for presence pulse from slave Delay_us(200); // Delay 435 microsecond (us) Delay_us(200); Delay_us(35); drive_OW_high (); // Release the bus return presence_detect;} </code></pre> <hr> <pre><code> void drive_OW_low (void){ LATHbits.LATH0 = 0; TRISHbits.TRISH0 = 0; }// Output </code></pre> <hr> <pre><code> void drive_OW_high (void){ LATHbits.LATH0 = 0; TRISHbits.TRISH0 = 1;} // Input </code></pre> <hr> <pre><code> uint8_t read_OW (void){ unsigned char read_data=0; TRISHbits.TRISH0 = 1; if (1 == PORTHbits.RH0) read_data = 1; else read_data = 0; return read_data;} </code></pre> <p>And now some ofthe important device_id:</p> <pre><code> void Device_ID( uint8_t command ){ uint8_t loop, family, checksum, ROM_CODE[8]; // 1 byte CRC, 6 bytes SERIAL, 1 byte Family code static char container[1]; OW_reset_pulse(); OW_write_byte( 0x33 ); // READ ROM COMMAND DS18B20 for(loop = 0; loop < 9; loop++) // 1 byte in per time = 64-bits { ROM_CODE[loop] = OW_read_byte(); } family = ROM_CODE[1]; checksum = ROM_CODE[8]; And so on = Print MY VALUES -> </code></pre> <hr> <pre><code> void OW_write_byte (uint8_t write_data){ uint8_t loop; for (loop = 0; loop < 8; loop++) { OW_write_bit(write_data & 0x01); //Sending LS-bit first write_data >>= 1; // shift the data byte for the next bit to send } } </code></pre> <hr> <pre><code> void OW_write_bit (uint8_t write_bit){ if (write_bit) // Write 1 time slot { Brakepoint(); // 1 us //writing a bit '1' drive_OW_low(); // Drive the bus low Delay_us(6); // Delay 6 microsecond (us) drive_OW_high (); // Release the bus Delay_us(64);; // Delay 64 microsecond (us) } else // Write 0 time slot { Brakepoint(); // 1 us //writing a bit '0' drive_OW_low(); // Drive the bus low Delay_us(65); // Delay 65 microsecond (us) drive_OW_high (); // Release the bus Delay_us(10); // Delay 10 microsecond for recovery (us) }} </code></pre> <hr> <pre><code> uint8_t OW_read_byte (void) uint8_t loop, result=0; for (loop = 0; loop < 8; loop++) { result >>= 1; // shift the result to get it ready for the next bit to receive if (OW_read_bit()) result |= 0x80; // if result is one, then set MS-bit } return result; } </code></pre> <hr> <pre><code> uint8_t OW_read_bit (void){ uint8_t read_data; // Reading a bit Brakepoint(); // 1 us drive_OW_low(); // Drive the bus low Delay_us(6); // delay 6 microsecond (us) drive_OW_high (); // Release the bus Delay_us(9); // delay 9 microsecond (us) read_data = read_OW(); //Read the status of OW_PIN Delay_us(55); // delay 55 microsecond (us) return read_data;} </code></pre>

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