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interfaces:1wire [2015/10/22 20:55] darron |
interfaces:1wire [2016/01/19 21:52] darron |
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| - | ==== 1wire ==== | + | ==== 1wire bus ==== |
| <wrap right> | <wrap right> | ||
| {{: | {{: | ||
| + | \\ \\ | ||
| + | {{: | ||
| + | \\ \\ | ||
| + | {{: | ||
| </ | </ | ||
| - | The 1wire bus supports various low speed digital devices and is supported in Linux. | + | The 1wire bus supports various low speed digital devices and is supported in Linux on the Raspberry Pi. |
| === Raspberry Pi === | === Raspberry Pi === | ||
| - | boot/ | + | Edit boot/ |
| < | < | ||
| dtoverlay=w1-gpio, | dtoverlay=w1-gpio, | ||
| </ | </ | ||
| + | |||
| + | 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| | ||
| + | |||
| + | The relevant pins on the Pi header are as follows. | ||
| + | < | ||
| + | +---P1---+ | ||
| + | 3V3 | ||
| + | GPIO0/ | ||
| + | GPIO1/ | ||
| + | GPIO4 07 2 08 GPIO14/TX | ||
| + | .. .. | ||
| + | </ | ||
| + | |||
| + | NB. The 1 wire data line must pulled high via 4K7 to 3V3 power. | ||
| + | |||
| === DS18B20 Thermometer === | === DS18B20 Thermometer === | ||
| < | < | ||
| + | +-------+ | ||
| + | | 1 2 3 | | ||
| + | +-------+ | ||
| + | | | | | ||
| + | | | | | ||
| + | | ||
| + | 1 GROUND | ||
| + | 2 DATA | ||
| + | 3 POWER | ||
| </ | </ | ||
| + | < | ||
| + | modprobe w1_therm | ||
| + | cat / | ||
| + | 8f 01 55 00 7f ff 0c 10 a0 : crc=a0 YES | ||
| + | 8f 01 55 00 7f ff 0c 10 a0 t=24937 | ||
| + | </ | ||
| + | |||
| + | === KEYES DS18B20 module === | ||
| + | |||
| + | This module re-orders the pins so beware. | ||
| + | |||
| + | < | ||
| + | +-------+ | ||
| + | |DS18B20| | ||
| + | | | | ||
| + | +-G R Y-+ | ||
| + | | | | | ||
| + | | ||
| + | G GROUND | ||
| + | R POWER | ||
| + | Y DATA | ||
| + | </ | ||
| + | |||
| + | DATA is pulled up via a 4K7 resistor and an LED. The LED will flash | ||
| + | during communication with the chip. | ||
| === DS2431 EEPROM === | === DS2431 EEPROM === | ||
| < | < | ||
| + | +-------+ | ||
| + | | 1 2 3 | | ||
| + | +-------+ | ||
| + | | | | | ||
| + | | | | | ||
| + | | ||
| + | 1 GROUND | ||
| + | 2 DATA | ||
| + | 3 NC | ||
| + | </ | ||
| + | |||
| + | < | ||
| + | modprobe w1_ds2431 | ||
| + | echo "hello world" > / | ||
| + | cat / | ||
| + | hello world | ||
| </ | </ | ||
