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products:sbc:common:applications:gpio:1wire

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products:sbc:common:applications:gpio:1wire [2022/07/06 06:26]
nick 		products:sbc:common:applications:gpio:1wire [2023/11/07 04:59] (current)
nick old revision restored (2023/11/07 04:42)
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 ===== Introduction ===== ===== Introduction =====
  
-This document will explain how to use 1-Wire bus on Khadas SBC. You will learn how to turn it on and how to get sensor data through 1-Wire bus.+This page introduces the usage of 1-Wire bus on [[products:sbc:common:applications:gpio:40pin-header|40-Pin Header]].
  
-===== Enable 1-Wire =====+===== 1-Wire Information =====
  
-You can enable 1-Wire bus via device tree overlay.+You can find the default PIN used for ''1-Wire'' bus from the table below.
  
-<tabbox VIM1/2/3/3L>+|           ^  PIN  ^  GPIO Name  ^  DT Overlays Node  ^  Device Node          ^ 
 +^  VIM1/2   |  37   |  GPIOH_5    |  onewire           |  /sys/bus/w1/devices  | 
 +^  VIM3/3L  |  15   |  GPIOH_6    | :::                | :::                   | 
 +^  VIM4     |  37   |  GPIOT_19   | :::                | :::                   | 
 +^  VIM1S    |  36   |  GPIOZ_8    | :::                | :::                   | 
 +^  Edge1    |  30   |  GPIO4_A0   | :::                | :::                   | 
 +|           |       |             | :::                | :::                   |
  
-Edit ''/boot/env.txt'' to add ''onewire'' to ''overlays'' node.+===== Enable 1-Wire Bus =====
  
-e.g. +In order to use the 1-Wire, you need to enable the ''1-Wire'' function via [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]]. 
-```sh + 
-overlays=uart4 pwm_ao_a pwm_f i2c0 onewire+<tabbox VIM1/2/3/3L/Edge1> 
 + 
 +Edit ''/boot/env.txt'' to add the onewire node to ''overlays'' node if it doesn't exist. 
 + 
 +Take VIM3 as an example to enable ''1-Wire'', you need to add ''onewire'' node to ''overlays'' node if it doesn't exist. 
 + 
 +```shell 
 +overlays=onewire
 ``` ```
 +<tabbox VIM3 with 5.15 kernel>
 +
 +Edit ''/boot/dtb/amlogic/kvim3.dtb.overlay.env'' to add onewire node to ''fdt_overlays'' node if it doesn't exist.
 +
 +
 +e.g. To enable onewire, you need to add ''onewire'' to node ''fdt_overlays'' if it doesn't exist.
 +
 +```shell
 +fdt_overlays=onewire
 +
 +```
 +
 +<tabbox VIM3L with 5.15 kernel>
 +
 +Edit ''/boot/dtb/amlogic/kvim3l.dtb.overlay.env'' to add onewire node to ''fdt_overlays'' node if it doesn't exist.
 +
 +
 +e.g. To enable onewire, you need to add ''onewire'' to node ''fdt_overlays'' if it doesn't exist.
 +
 +```shell
 +fdt_overlays=onewire
 +
 +```
 +
 <tabbox VIM4> <tabbox VIM4>
  
-Edid ''/boot/dtb/amlogic/kvim4.dtb.overlay.env'' to add ''onewire'' to ''fdt_overlays'' node.+Edit ''/boot/dtb/amlogic/kvim4.dtb.overlay.env'' to add onewire node to ''fdt_overlays'' node if it doesn't exist.
  
-e.g.  
  
-```sh+e.g. To enable onewire, you need to add ''onewire'' to node ''fdt_overlays'' if it doesn't exist. 
 + 
 +```shell
 fdt_overlays=onewire fdt_overlays=onewire
  
 ``` ```
 +<tabbox VIM1S>
  
-</tabbox>+Edit ''/boot/dtb/amlogic/kvim1s.dtb.overlay.env'' to add onewire node to ''fdt_overlays'' node if it doesn't exist.
  
-Reboot to effect. 
  
-<WRAP info > +e.g. To enable onewire, you need to add ''onewire'' to node ''fdt_overlays'' if it doesn't exist. 
-For details on overlays, please refer to [[products:sbc:vim4:configurations:device-tree-overlay|Device Tree Overlay]].+ 
 +```shell 
 +fdt_overlays=onewire 
 + 
 +``` 
 +</tabbox> 
 + 
 +<WRAP tip > 
 +Reboot the system for this change to take effect.
 </WRAP> </WRAP>
  
-===== Get sensor data =====+ 
 +===== Get Sensor Data =====
  
 Here we attach a 1-Wire device ''DS18B20'' temperature sensor to the 1-Wire bus. Here we attach a 1-Wire device ''DS18B20'' temperature sensor to the 1-Wire bus.
  
 Enter the driver directory: Enter the driver directory:
-```sh+```shell
 khadas@Khadas:~$ cd /sys/bus/w1/devices khadas@Khadas:~$ cd /sys/bus/w1/devices
 khadas@Khadas:/sys/bus/w1/devices$ ls khadas@Khadas:/sys/bus/w1/devices$ ls
Line 48: Line 95:
  
 You can see the node of ''ds18b20'' is ''28-0119395ebf91''. Enter this directory: You can see the node of ''ds18b20'' is ''28-0119395ebf91''. Enter this directory:
-```sh+```shell
 khadas@Khadas:/sys/bus/w1/devices$ cd 28-0119395ebf91 khadas@Khadas:/sys/bus/w1/devices$ cd 28-0119395ebf91
 khadas@Khadas:/sys/bus/w1/devices/28-0119395ebf91$ ls khadas@Khadas:/sys/bus/w1/devices/28-0119395ebf91$ ls
Line 55: Line 102:
  
 Read ''w1_slave'' file will get the temperature value: Read ''w1_slave'' file will get the temperature value:
-```sh+```shell
 khadas@Khadas:/sys/bus/w1/devices/28-0119395ebf91$ cat w1_slave khadas@Khadas:/sys/bus/w1/devices/28-0119395ebf91$ cat w1_slave
 b1 01 4b 46 7f ff 0c 10 d8 : crc=d8 YES b1 01 4b 46 7f ff 0c 10 d8 : crc=d8 YES
Line 61: Line 108:
 ``` ```
  
-Physical pins of 1-Wire bus: + 
-<tabbox VIM1>  +===== Disable 1-Wire to Use GPIO ===== 
-''GPIOH_5'' - PIN37 + 
-<tabbox VIM2>  +If you want to use normal GPIO instead of 1-Wire, you can remove the 1-Wire node in [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]]. 
-''GPIOH_5'' - PIN37 +
-<tabbox VIM3/3L>  +
-''GPIOH_6'' - PIN15 +
-<tabbox Edge1> +
-''GPIO4_A0'' - PIN30 +
-<tabbox VIM4>  +
-''GPIOT_19'' - PIN37 +
-</tabbox>+
Last modified: 2022/07/06 06:26 by nick

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