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en:iot-open:embeddedcommunicationprotocols2:1wire [2023/08/25 08:40] – ekontoturboen:iot-open:embeddedcommunicationprotocols2:1wire [2024/05/27 11:18] (current) – ktokarz
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-===== 1-Wire ===== +====== 1-Wire ====== 
-1-Wire is a master-slave communication asynchronous bus interface designed formerly by Dallas Semiconductor Corp((https://www.maximintegrated.com/en/products/digital/one-wire.html)). It can transmit data at long distances at the cost of transmission speed. The typical data speed of the 1-Wire interface is about 16.3 kbit/s, and the maximum length is approx. 300m. Name 1-Wire comes from the feature that the data line can directly power elements connected to the bus. A network chain of 1-Wire devices consists of one master device and many slave devices. Such a chain is called a MicroLAN. 1-Wire devices may be a part of a product's circuit board, a single component device such as a temperature probe, or a remote device for monitoring purposes. +{{:en:iot-open:czapka_b.png?50| General audience classification icon }}{{:en:iot-open:czapka_e.png?50| General audience classification icon }}\\ 
 +1-Wire is a master-slave communication asynchronous bus interface designed formerly by Dallas Semiconductor Corp((https://www.maximintegrated.com/en/products/digital/one-wire.html)). It can transmit data at long distances at the cost of transmission speed. The typical data speed of the 1-Wire interface is about 16.3 kbit/s, and the maximum length is approx. 300m. Name 1-Wire comes from the feature that the data line can directly power elements connected to the bus. A network chain of 1-Wire devices consists of one master device and many slave devices (figure {{ref>1wire0}}). Such a chain is called a MicroLAN. 1-Wire devices may be a part of a product's circuit board, a single component device such as a temperature probe, or a remote device for monitoring purposes. 
  
 Each 1-Wire device must contain a logic unit to operate on the bus. A dedicated bus converter is needed to connect a 1-wire bus to a PC. The most popular PC/1-Wire converters use a USB plug to connect to the PC and the RJ11 connectors (telephones 6P2C/6P4C modular plugs) for MicroLAN. 1-Wire devices can also be connected directly to the microcontroller boards. Each 1-Wire device must contain a logic unit to operate on the bus. A dedicated bus converter is needed to connect a 1-wire bus to a PC. The most popular PC/1-Wire converters use a USB plug to connect to the PC and the RJ11 connectors (telephones 6P2C/6P4C modular plugs) for MicroLAN. 1-Wire devices can also be connected directly to the microcontroller boards.
  
-==== 1-Wire Protocol Description ====+===Protocol Description ===
 Within the MicroLAN, there is always one master device, typically a PC or a microcontroller unit. The master always initiates activity on the bus to avoid collisions on the network chain. If a collision occurs, the master device retries the communication. In the 1-Wire network, many devices can share the same bus line. To identify devices in the MicroLAN, each connected device has a unique 64-bit ID number. The ID number's least significant byte defines the type of the device (temperature, voltage, etc.). The most significant byte represents a standard 8-bit CRC.  Within the MicroLAN, there is always one master device, typically a PC or a microcontroller unit. The master always initiates activity on the bus to avoid collisions on the network chain. If a collision occurs, the master device retries the communication. In the 1-Wire network, many devices can share the same bus line. To identify devices in the MicroLAN, each connected device has a unique 64-bit ID number. The ID number's least significant byte defines the type of the device (temperature, voltage, etc.). The most significant byte represents a standard 8-bit CRC. 
 The 1-Wire protocol description contains several broadcast commands and commands used to address the selected device. The master sends a selection command, then the address of the selected slave device. This way, the following command is executed only by the addressed device. The 1-Wire bus implements an enumeration procedure that allows the master to get information about the ID numbers of all connected slave devices to the MicroLAN network. The device address includes the device type, identifying what type of slaves are connected to the network chain. The 64-bit address space is searched as a binary tree. It makes it possible to find up to 75 devices per second.  The 1-Wire protocol description contains several broadcast commands and commands used to address the selected device. The master sends a selection command, then the address of the selected slave device. This way, the following command is executed only by the addressed device. The 1-Wire bus implements an enumeration procedure that allows the master to get information about the ID numbers of all connected slave devices to the MicroLAN network. The device address includes the device type, identifying what type of slaves are connected to the network chain. The 64-bit address space is searched as a binary tree. It makes it possible to find up to 75 devices per second. 
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 The physical implementation of the 1-Wire network is based on an open drain master device connected to one or more open drain slaves. One single pull-up resistor for all devices pulls the bus up to 3/5 V and can be used to power the slave devices. 1-Wire communication starts when a master or slave sets the bus to low voltage (connects the pull-up resistor to ground through its output MOSFET).  The physical implementation of the 1-Wire network is based on an open drain master device connected to one or more open drain slaves. One single pull-up resistor for all devices pulls the bus up to 3/5 V and can be used to power the slave devices. 1-Wire communication starts when a master or slave sets the bus to low voltage (connects the pull-up resistor to ground through its output MOSFET). 
  
-<figure label> +<figure 1wire0> 
-{{ en:iot-open:embeddedcommunicationprotocols2:1wire_bus.png?nolink&450 | 1-Wire bus}}+{{ en:iot-open:embeddedcommunicationprotocols2:1wire_bus.png?450 | 1-Wire bus connection}}
 <caption>1-Wire bus connection</caption> <caption>1-Wire bus connection</caption>
 </figure> </figure>
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 To find the devices, the enumeration broadcast command must be sent by a master. The slave device responds with all ID bits to the master, and at the end, it returns a 0. To find the devices, the enumeration broadcast command must be sent by a master. The slave device responds with all ID bits to the master, and at the end, it returns a 0.
  
-<figure label> +Sample 1-Wire timings are present in figures {{ref>1wire1}}, {{ref>1wire2}} and {{ref>1wire3}}. 
-{{ en:iot-open:embeddedcommunicationprotocols2:1wire_reset.png?nolink&450 | 1-Wire reset timings}}+ 
 +<figure 1wire1> 
 +{{ en:iot-open:embeddedcommunicationprotocols2:1wire_reset.png?450 | 1-Wire reset timings}}
 <caption>1-Wire reset timings</caption> <caption>1-Wire reset timings</caption>
 </figure> </figure>
  
-<figure label> +<figure 1wire2> 
-{{ en:iot-open:embeddedcommunicationprotocols2:1wire_read.png?nolink&450 | 1-Wire read timings}}+{{ en:iot-open:embeddedcommunicationprotocols2:1wire_read.png?450 | 1-Wire read timings}}
 <caption>1-Wire read timings</caption> <caption>1-Wire read timings</caption>
 </figure> </figure>
  
-<figure label> +<figure 1wire3> 
-{{ en:iot-open:embeddedcommunicationprotocols2:1wire_write.png?nolink&450 | 1-Wire write timings}}+{{ en:iot-open:embeddedcommunicationprotocols2:1wire_write.png?450 | 1-Wire write timings}}
 <caption>1-Wire write timings</caption> <caption>1-Wire write timings</caption>
 </figure> </figure>
- 
  
 === 1-Wire Products === === 1-Wire Products ===
-The Dallas/Maxim integrated 1-Wire devices list contains a wide range of implementations. The 1-Wire protocol can be quickly implemented into the current IoT boards; most manufacturers share the software libraries, allowing developers to include them in their projects in C, C++, and assembly languages. The 1-Wire sensors (temperature, humidity, pressure, etc.) are factory calibrated and reading the physical measurements follows the International System of Units (SI). 1-Wire products can be grouped as follows:+The Dallas/Maxim integrated 1-Wire devices list contains many implementations. The 1-Wire protocol can be quickly implemented into the current IoT boards; most manufacturers share the software libraries, allowing developers to include them in their projects in C, C++, and assembly languages. The 1-Wire sensors (temperature, humidity, pressure, etc.) are factory-calibrated and read the physical measurements following the International System of Units (SI). 1-Wire products can be grouped as follows:
   *   secure authenticators,   *   secure authenticators,
   *   memory EPROM, EEPROM ROM,   *   memory EPROM, EEPROM ROM,
en/iot-open/embeddedcommunicationprotocols2/1wire.1692952812.txt.gz · Last modified: 2023/08/25 05:40 (external edit)
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