40 lines
1.1 KiB
Markdown
40 lines
1.1 KiB
Markdown
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# DS18B20
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A very popular digital thermometer, temperature monitoring with 2-wire or 3-wire Connections.
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# Wiring
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## Normal Power Mode
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3-wire connection of normal power mode
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* P35 -> DQ
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* GND -> GND
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* 5V/3.3V -> VDD
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## Parasite Power Mode:
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In parasite power mode, it's a 2-wire connection. It requires both DS18B20 GND and Vdd to be connected to ground. The DQ pin is the data/parasite power line, which requires a pull-up resistor (set by PxPU command).
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It has to be noted that **not** all DS18B20 you bought online works in parasite mode. There are cheap units that output `0` only in parasite mode, in this case you need some modifications to make it work.
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* P35 -> DQ
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* GND -> GND -> VDD
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* 5V
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## Parasite Power Mode Emulation:
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In case some DS18B20 doesn't work in parasite mode, you can add one 0.1uF capacitor and one 1N4148 to achieve 2-wire connection.
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In thise way DS18B20 actually works in normal power mode
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```
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+-----1N4148-|>|-----+
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| |DS18B20|-VCC--+
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P35 --+-DQ--|DS18B20| 0.1uF
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GND ----GND-|DS18B20|-GND--+
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```
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