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--- interfaces:1wire [2015/10/22 21:10]
darron [Raspberry Pi]
+++ interfaces:1wire [2016/01/20 10:21] (current)
darron [KEYES DS18B20 module]
@@ Line 1: / Line 1: @@
-==== 1wire ====
+==== 1wire bus ====
 <wrap right>
 {{:interfaces:1wire.jpg?200}}
+\\ \\
+{{:interfaces:1wire-2.jpg?200}}
+\\ \\
+{{:interfaces:keyes.jpg?200}}
 </wrap>
@@ Line 17: / Line 21: @@
 modprobe w1_gpio
 </code>
+These are the GPIO header pin assignments for the 1 wire bus.
 ^Pin ^Name  ^Function |
-| 1  | 3V3 | POWER
+| 1  | 3V3 | POWER|
 | 6  | GND| GROUND |
 | 7  | GPIO4 | DATA|
+The relevant pins on the Pi header are as follows.
+<code>
+                +---P1---+
+V3             01      02 5V
+GPIO0/GPIO2     03 A/A+ 04 5V
+GPIO1/GPIO3     05 B/B+ 06 GND
+GPIO4           07 2    08 GPIO14/TX
+                ..      ..
+</code>
+NB. The 1 wire data line must pulled high via 4K7 to 3V3 power.
 === DS18B20 Thermometer ===
 <code>
@@ Line 42: / Line 62: @@
 </code>
+=== KEYES KY-001 DS18B20 module ===
+This module re-orders the pins so beware.
+<code>
++-------+
+|DS18B20|
+|       |
++-G R Y-+
+  | | |
+G GROUND
+R POWER
+Y DATA
+</code>
+DATA is pulled up via a 4K7 resistor and an LED. The LED will flash
+during communication with the chip.
 === DS2431 EEPROM ===
 <code>