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1wire bus

1wire.jpg

1wire-2.jpg

The 1wire bus supports various low speed digital devices and is supported in Linux on the Raspberry Pi.

Raspberry Pi

Edit boot/config.txt to assign gpio4 for 1wire.

dtoverlay=w1-gpio,gpiopin=4

Reboot and after load driver.

modprobe w1_gpio

These are the GPIO header pin assignments for the 1 wire bus.

Pin Name Function
1 3V3 POWER
6 GND GROUND
7 GPIO4 DATA

Data is pulled high via 4K7 to 3V3 power.

DS18B20 Thermometer

+-------+
| 1 2 3 |
+-------+
  | | |
  | | |
  
1 GROUND
2 DATA
3 POWER
modprobe w1_therm
cat /sys/bus/w1/devices/28-041460bdd6ff/w1_slave 
8f 01 55 00 7f ff 0c 10 a0 : crc=a0 YES
8f 01 55 00 7f ff 0c 10 a0 t=24937

DS2431 EEPROM

+-------+
| 1 2 3 |
+-------+
  | | |
  | | |
  
1 GROUND
2 DATA
3 NC
modprobe w1_ds2431
echo "hello world" > /sys/bus/w1/devices/2d-00000de5d608/eeprom
cat /sys/bus/w1/devices/2d-00000de5d608/eeprom
hello world

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