Forem: EBYTE

What is CAN?

EBYTE — Fri, 01 Sep 2023 05:13:49 +0000

CAN is the abbreviation of Controller Area Network (hereinafter referred to as CAN), which is an ISO internationally standardized serial communication protocol. In the automotive industry, various electronic control systems have been developed due to requirements for vehicle safety, comfort, convenience, low power consumption, low cost, etc. Since the data types and reliability requirements used for communication between these electronic control systems are different, and they are often composed of multiple buses, the number of wire harnesses also increases with the composition.

In order to meet the needs of "appropriately reducing the number of wire harnesses" and "carrying out high-speed data communication between large amounts of data through multiple LANs", in 1986 the German electrical company Bosch developed a CAN communication protocol for the automotive industry. After the introduction of this protocol, CAN was standardized through ISO11898 and ISO11519, becoming the European standard protocol in the automotive industry network control system.

CAN bus data format

CAN-BUS communication frames are divided into data frames, remote frames, error frames, overload frames and frame intervals.

Data frame: Structurally composed of 7 segments, which are divided into standard frames (CAN2.0A) and extended frames (CAN2.0B) according to the length of the arbitration segment ID code. The standard frame is 11 bits, and the extended frame is 29 bits. This is also the format we come into contact with the most.

Remote frame: Compared with data frame, there is no data segment and the structure is composed of 7 segments. When you need a node on the bus to send you data, send a remote frame using the ID of the secondary node. The biggest advantage of remote frames is that it only takes one frame to complete a two-way interaction.

Error frame: Although the CAN bus is a highly reliable bus, errors can still occur: 5 types of errors will appear on the CAN bus.

Overload frame: When a node is not ready to receive the next frame of data, it will send an overload frame to notify the node.

Frame interval: only exists between data frames and remote frames, used for separation between frames.

Communication characteristics of CAN bus

CAN bus is a serial data communication protocol developed by German BOSCH in the early 1980s to solve the problem of data exchange between many control and test systems in modern automobiles. It can use twisted pairs, coaxial cables or light guides. Fiber is used as a multi-master bus as the communication medium. Communication rate up to 1Mbps.

(1) Free communication can be achieved between nodes: One of the biggest features of the CAN protocol is that it abolishes the traditional station address encoding and replaces it with encoding the communication data block. The advantage of using this method is that, in theory, the number of network nodes composed of CAN is not limited. The identifier of the data block can be composed of 11-bit or 29-bit binary numbers, so two or more different data blocks can be defined. This method of encoding by data block can also enable different nodes to receive the same data at the same time. This is very useful in distributed control systems.

(2) Simple structure: only 2 wires are connected to the outside, and error detection and management modules are integrated internally.

(3) Data error correction: Two-wire serial communication mode is adopted, which has strong error detection ability and can work in high noise interference environment. Each frame of data has CRC check and other error detection measures to ensure high reliability of data transmission performance, suitable for use in high interference environments.

(4) Complete the framing processing of communication data: the CAN bus communication interface integrates the physical layer and data link layer functions of the CAN protocol, which can complete the framing processing of communication data, including data bit filling, data block encoding, Cyclic redundancy check, priority discrimination, etc.

The characteristics of CAN's high performance and reliability have now been recognized and widely used in industries such as industrial automation, ships, medical equipment, and industrial equipment automation. CAN bus seems to be one of the hottest technological developments in the field of automation today, and is known as the computer local area network in the field of automation. Its emergence provides powerful technical support for distributed control systems to achieve real-time and reliable data communication between nodes.

Why do you need the RPC protocol when you have the HTTP transport protocol?

EBYTE — Tue, 08 Aug 2023 03:23:12 +0000

Before explaining, we first need to understand what is the HTTP protocol and what is the RPC protocol.
What is the HTTP protocol

HTTP is a widely used network transmission protocol. The HTTP protocol defines the communication format and communication method between the client (such as browser, mobile phone user APP, etc.) It is a communication model based on request-response, that is, the server returns a response according to the request. Both the request and the response contain some information about the interaction between the two ends (client, server), such as method and header. section, text, etc.

Basic flowchart of HTTP interaction

Figure 1 Basic flowchart of HTTP interaction

The HTTP protocol has many advantages. The HTTP transport protocol supports multiple data formats and encoding methods, and can realize cross-platform and cross-language communication. The communication is simple, flexible, and easy to expand. But at the same time, the HTTP protocol also has some disadvantages:

1) The HTTP transport protocol is stateless, and the connection needs to be re-established for each request, which will increase network overhead and delay.

2) The data transmission of the HTTP transmission protocol is based on text, which will result in a large amount of data and low parsing efficiency.

3) The security of the HTTP transmission protocol is poor, and it is vulnerable to man-in-the-middle attacks and replay attacks.

4) The semantics of the HTTP transport protocol is weak, and it can only express basic addition, deletion, modification and query operations, and cannot satisfy complex business logic.
What is the RPC protocol

RPC, or Remote Procedure Call, is a remote procedure call protocol that allows a client to call a function on a remote server as if it were a local function.

RPC protocol interaction process

Figure 2 RPC protocol interaction process

The advantages of the RPC protocol are efficient, powerful, and easy to use, but it also has some disadvantages, such as:

1) The RPC protocol is stateful and needs to maintain the connection state between the client and the server, which will increase the complexity and resource consumption of the system.

2) The data transmission of the RPC protocol is based on binary, which makes the data difficult to read and debug.

3) The compatibility of the RPC protocol is poor, and there may be inconsistencies in protocols and interfaces between different RPC frameworks.

4) The scalability of the RPC protocol is poor, and it is difficult to support functions such as dynamic service discovery and load balancing.

To sum up, in actual use, the HTTP protocol and the RPC protocol have their own advantages and disadvantages, and there is no absolute distinction between good and bad. Choose the appropriate protocol for different usage scenarios. for example:

1) In the microservice architecture, frequent internal calls are required between services, and the RPC protocol can provide higher performance and reliability.

2) In distributed computing, a large number of computing tasks need to be distributed to different nodes for execution. The RPC protocol can achieve a more flexible load balancing and fault tolerance mechanism.

3) In real-time communication, low-latency and high-concurrency data exchange needs to be realized. The RPC protocol can support multiple transmission protocols and communication modes.

4) If you need to achieve cross-platform and cross-language communication, or you need to support multiple data formats and encoding methods, or you need to use the existing HTTP protocol infrastructure and tools, you can choose the HTTP protocol.

Of course, this is not an absolutely fixed combination. You can also combine the two protocols to achieve a better network, for example:

1) We can encapsulate the RPC protocol on the HTTP protocol, so that the RPC protocol request can be forwarded and processed through the HTTP proxy or gateway.

2) We can use the HTTP protocol as the transport layer on the RPC protocol, so that RPC protocol requests can use the characteristics of HTTP to implement caching, compression, encryption and other functions.

So in general, the emergence of RPC is to deal with network scenarios that require performance that cannot be met by the HTTP protocol. They are not mutually exclusive, but can be selected and combined according to different scenarios and needs.

Ways to reduce the power consumption of BLE equipment

EBYTE — Mon, 31 Jul 2023 09:51:59 +0000

We all know that BLE is Bluetooth low energy technology, which can effectively reduce the power consumption of Bluetooth devices, so that the device can have a good use time under battery power.But you may not know that even the same BLE equipment will produce different power consumption rates under different conditions of use. What causes the power consumption of BLE equipment to change?Today we will take a look.

Before introducing specific factors, we need to know some basic knowledge: BLE host devices are generally in one of the three states of standby, scanning, and connection, while BLE slave devices are in one of the standby, broadcast, and connection states.When the BLE device is not connected, the device will wake up intermittently and broadcast and scan. Except for the broadcast and scan time, the rest of the time will go to sleep to ensure reduced power consumption.

Under the premise of understanding this basic knowledge, let's take a look at what can affect the low-power performance of BLE equipment.

The first is the broadcast (scan) interval of the device

When the device is not connected, the BLE device will continue to broadcast (scan) intermittently. The shorter the interval between each two broadcasts (scans), the more times the device will wake up per unit time, which will naturally increase the power consumption level of the device.Therefore, a reasonable increase in the broadcast (scanning) interval of BLE equipment can effectively reduce the power consumption of the equipment.

However, it needs to be known that in addition to affecting the low-power performance of the device, the broadcast (scan) interval of the device will also affect the connection speed of the device. Too long broadcast (scan) interval will significantly increase the connection speed of the BLE and affect the user experience.Therefore, between low power consumption and connection speed, users need to make a trade-off and choose a level that they can accept.

The second is the duration of the device broadcast (scan)

That is, in the broadcast (scan) mode, the duration of each broadcast (scan) of the device.The principle is similar to the interval mentioned earlier. The longer the duration of the broadcast (scan), the longer the device will be awakened per unit time, and the shorter the sleep time, which will increase the power consumption level of the device.Similarly, the longer the duration of the broadcast (scan), the faster the connection response speed of the device can be effectively improved, and vice versa.

Then the connection interval of the device

After the device enters the connection mode, the host device of BLE will send a connection event to the BLE device. After the device receives this event, it will immediately reply to the event to notify the host device that the connection link is normal.The transmission and reply of this data is the highest power consumption after the entire BLE connection, so if you can increase the connection interval, you can effectively reduce the average power consumption level per unit time and effectively reduce power consumption.However, as mentioned earlier, if the power consumption of the device is reduced by increasing the connection interval, the communication response speed of the device will be slowed down. Therefore, when adjusting this parameter, it is necessary to consider whether the communication speed can be accepted by the user.

Finally ignored by the slave

That is, the number of events that the device can ignore when it is connected.In each connection, the BLE host will first send data, and then the device will reply. If the reply is not received, the host will think that the device status is abnormal.However, after setting the number of slave delays, the device will be allowed to not reply to the host for a certain number of times. Failure to reply within the set number of times will not cause the host to judge abnormally.This reduces the overall power consumption of the device by reducing the number of replies.

Chengdu Yibaite Electronic Technology Co., Ltd. specializes in the research and development and production of wireless data transmission modules with various functions in various frequency bands. The products have been widely used in various application scenarios such as the Internet of Things, consumer electronics, industrial control, medical, smart home, highway, etc. If you have any needs, please contact email:service-es-@cdebyte.com Or visit the website:https://www.es-ebyte.com/

Analysis of the relationship between SAE-J1939 and CAN2.0B

EBYTE — Fri, 28 Jul 2023 08:18:27 +0000

What is SAE-J1939?

SAE-J1939 (hereinafter referred to as J1939) is the recommended standard of the American Society of Automotive Engineers (SAE), widely used in commercial vehicles (heavy trucks, buses and other road vehicles and construction machinery, agricultural machinery, rail locomotives, ships and other non-road vehicles and equipment) ) Digital communication between electronic components.

The relationship between SAE-J1939 and CAN2.0

CAN2.0 (previous guide) is a bus specification and a data link layer technology. J1939 is a specification defined by SAE (American Automobile Association) based on the CAN bus, and is mainly used to solve compatibility issues between different engine manufacturers and different ECU manufacturers.

J1939 defines a series of PGNs and SPNs. These PGNs contain information on various parts of the car such as engines, transmissions, and axles; the representation method (state and value) of parameters defines SLOT (Scaling-proportion, Limit-boundary, Offset—offset, Transfer—transfer). ECU manufacturers should follow this specification when developing equipment. ECU modules have different functions and different manufacturers. On the basis of J1939, they show their diversity: support or not support some PGN, SPN and SLOT; add some PGN and SPN that are not defined by J1939.

SAE-J1939 and CAN2.0B message frame format

The CAN2.0 specification includes CAN2.0A (standard frame format) and CAN2.0B (extended frame format), both of which use different frame format bitcodes. J1939 is further packaged on the basis of CAN2.0B, redefining the 29-bit ID of the arbitration field. Only standardized communication is defined for the extended frame format in SAE-J1939, therefore, SAE-1939 equipment must use the extended frame format.

**_Ebyte Electronic Technology Co., Ltd. specializes in R&D and production of wireless data transmission modules with various functions in various frequency bands. The products have been widely used in various application scenarios such as the Internet of Things, consumer electronics, industrial control, medical care, smart home, and highways. If you have any needs, please contact email:

service-es-@cdebyte.com
or visit the website: https://www.es-ebyte.com/Module-SPISOCUART_**

Four types of routing mechanisms in the ZigBee protocol

EBYTE — Thu, 27 Jul 2023 08:03:51 +0000

ZigBee routing has the following types
Table Routing
Broadcast Routing
Multicast Routing
Many-to-One/Source Routing

Part 1
Table Routing
In order for the source node to discover the path to the target node, the source node first sends a route discovery request to form a routing table. When a route between two nodes is established, the source node only needs to send data to the first node in the route, which is stored in the routing table of the source node.

Therefore, each intermediate node forwards the data to the next node of the route by querying its own routing table until the data reaches the target node. If the routing fails, the routing error is sent back to the source node, and then the source node can re-initiate the route discovery request.

Part 2
Broadcast Routing
Broadcast routing is a routing mechanism that sends messages to all devices in the network. The network layer broadcast has an option to choose whether to send the message to the routing device only, or to the non-sleeping terminal device, or to the sleepy terminal device.

The following table, set by broadcast address

A broadcast message will be repeated 3 times by all routing devices in the network to ensure delivery to all devices. While broadcasting is a reliable method of sending messages, it should be used with caution due to the impact on network performance.

Repeated broadcasts may limit other ongoing communications on the network. Broadcasting is also not a reliable way to send messages to sleeping devices, because the parent device is responsible for buffering messages to the sleeping child device, but may lose the message before the sleeping child device wakes up.

Part 3

Multicast Routing
Multicast routing provides routing options for one-to-many communications. Multicasting is used when one device wants to send a message to a group of devices, for example a switch sends a turn-on command to 10 lights. Under this mechanism, all devices join a group.
Only those devices that are members of the group will receive the messages, while other devices will route and forward these multicast messages. Multicast can be understood as a restricted broadcast, and too much use will reduce network performance, and neither broadcast nor multicast has ACK.

Part 4
Many-to-One/Source Routing
Many-to-One Routing is a simple routing mechanism that enables routing devices in the entire network to have a route back to the central node (concentrator). Under this mechanism, the central node (concentrator) periodically sends Many -to-One route discovery broadcast (default 60 seconds can be set according to requirements).
When the routing device in the network receives this broadcast, it has the next-hop route back to the central node (concentrator), and stores this hop node information in its own routing table. So far, as long as the routing devices in the network receive the broadcast of Many-to-One route discovery, they will know the route back to the central node (concentrator).
As shown in the figure below, C periodically broadcasts Many-to-One route discovery, and all routing devices in the network know the routing information from themselves to C, and update their routing tables at the same time.

Source routing refers to the routing mechanism that the central node (concentrator) will send to other routing devices. For the central node (concentrator), it does not yet know the downlink route, that is, the route for sending information to each routing device is not yet known. Therefore, when each routing device sends unicast to the central node, it will send a Route Record to the central node before that. The central node receives this Route Record, reverses this route and stores it in the Source routing table of the central node (the size of the table needs to store the source routing information of all routing devices in the network). In this way, the central node can obtain the route sent to the destination node by querying the Source routing table.

As shown in the figure below, when R1 sends unicast data to C, it will first send its own routing information to C, and when C receives the routing information from R1, it will reversely store the route in its own source routing table. The routing table will record the routing information of all routing devices in the network.

In short, as long as the routing device receives the Many-to-One route discovery broadcast, it knows the route back to the central node. As long as there is information about the routing device in the Source routing table of the central node, the central node knows the route to the routing device.

If the central node (concentrator) is reset or powered off and restarted under abnormal circumstances, all the information in its Source routing table will be lost. At this time, a corresponding mechanism is required to restore its Source routing table. In this case, the central node (concentrator) can broadcast Many-to-One first.
Route discovery, and then broadcast a piece of data to each routing node, so that the routing node will reply a unicast to the central node (concentrator), and the routing node will send a Route Record before sending this unicast, so the central node can update its Source routing surface.

If all the routing nodes are powered off or restarted under certain abnormal conditions, the routing table of each routing node will also be lost. At this time, it is necessary to wait for at least 16 seconds. After each routing node establishes a link with the neighboring routing node, Then the central node (concentrator) sends the Many-to-One route discovery broadcast. Once each routing node device receives the Many-to-One route discovery broadcast, it has a route back to the central node.

Ebyte Electronic Technology Co., Ltd. specializes in R&D and production of wireless data transmission modules with various functions in various frequency bands. The products have been widely used in various application scenarios such as the Internet of Things, medical care, smart homes, and highways. If you have any needs, please contact email: service-es-@cdebyte.com or visit the website: https://www.es-ebyte.com/

Ethernet-PHY, MAC, MII and network card

EBYTE — Wed, 26 Jul 2023 09:32:32 +0000

A Network Interface Card (NIC for short), also known as a network adapter, is a device that connects a computer to a local area network.As long as you connect to the local area network, you need a network card.A network card mainly includes the bottom two layers of OSI, the physical layer and the data link layer.The chip at the physical layer is called the PHY, and the chip at the data link layer is called the MAC controller.

The purpose of this article is to learn the basic MAC and PHY knowledge of Ethernet, summarize the system framework and physical hardware composition principles, and understand various interfaces.
PHY & MAC & MII

PHY

PHY is a physical interface transceiver, which implements the physical layer.It includes the MII/GMII (media independent interface) sublayer, PCS (physical coding sublayer), PMA (physical media additional) sublayer, PMD (physical media related) sublayer, and MDI sublayer.Defines the electrical and optical signals, line status, clock reference, data coding, and circuits required for data transmission and reception, and provides a standard interface to the data link layer equipment.The chip at the physical layer is called PHY.

MAC

MAC is an abbreviation for Media Access Control, which is the media access control sublayer protocol.This protocol is located in the lower half of the data link layer in the OSI Layer 7 protocol, and is mainly responsible for controlling and connecting the physical media of the physical layer.

When sending data, the MAC protocol can determine in advance whether the data can be sent. If it can be sent, some control information will be added to the data, and finally the data and control information will be sent to the physical layer in a specified format; when receiving data, the MAC protocol first determines whether the input information has a transmission error, if there is no error, then the control information is removed and sent to the LLC layer.Ethernet MAC is defined by the IEEE-802.3 Ethernet standard.

MII

MII is the media independent interface, also known as the media independent interface.It is the Ethernet industry standard defined by IEEE-802.3.It includes a data interface and a management interface between MAC and PHY.The data interface includes two independent channels for the transmitter and receiver, respectively.Each channel has its own data, clock, and control signals.

The MII data interface requires a total of 16 signals.The management interface is a dual-signal interface: one is a clock signal and the other is a data signal.Through the management interface, the upper layer can monitor and control the PHY.

It can be seen that MAC and PHY, one is the data link layer and the other is the physical layer; both transmit data through MII.

System composition

From the perspective of hardware, the circuit interface of Ethernet is generally composed of CPU, MAC (Media Access Control) controller, and physical layer interface PHY.：
picture
For the above three parts, not all of them are independent chips, there are mainly the following situations：
(1) MAC and PHY are integrated inside the CPU, which is more difficult；
(2) The CPU integrates the MAC internally, and the PHY adopts an independent chip (mainstream solution)；
(3) The CPU does not integrate MAC and PHY, and MAC and PHY use independent chips or integrated chips (high-end use).

PHY integrates a large amount of analog hardware, and MAC is a typical all-digital device. The reason for the chip area and the analog/digital hybrid architecture is that the MAC is integrated into the microcontroller and the PHY is left off-chip.More flexible and denser chip technology can already realize the single-chip integration of MAC and PHY.

Taking the commonly used CPU internally integrates the MAC, and the PHY adopts an independent chip scheme as an example. The dotted line indicates that the CPU and the MAC are integrated together, and the PHY chip is interconnected with the MAC on the CPU through the MII interface.

For this scheme, the hardware scheme is simpler than the independent one. There are the following two important hardware interfaces between PHY and MAC.：
(1) The MDIO bus interface is mainly to complete the register configuration of the CPU for the PHY chip.；
(2) MII is the media independent interface, also known as the media independent interface.The common ones are MII, RMII, GMII, RGMII, etc."Media independence" indicates that ANY type of PHY device can work properly without redesigning or replacing the MAC hardware.The MII data interface requires a total of 16 signals, including:
transmit data - TXD[3:0]
transmit strobe - TX_EN
transmit clock - TX_CLK
transmit error - TX_ER/TXD4
receive data - RXD[3:0]
receive strobe - RX_DV
receive clock - RX_CLK
receive error - RX_ER/RXD4
collision indication - COL
carrier sense - CRS
Generally speaking, it includes a set of signals used by the IC to read and write PHY: MDC (clock), MDIO (data) as two sets of clocks for data sampling reference, the frequency should be 25MHz (TX_CLK, RX_CLK) each 4-bit output and input Bus (TX[0:3], RX[0:3]); notify the other party to prepare the output of the input data, the input start signal (TX_EN); the output and input error notification signal (TX_ER, RX_ER); a notification signal (RX_DV) to obtain valid input data; a colision signal (Col) for network congestion.
As a signal (CRS) for carrier recovery, the potential can be +5V or +3.3V.

MII transmits data in both directions in 4bit, that is, nibble mode, with a clock rate of 25MHz and an operating rate of up to 100Mb/S.MII transmits all the data and data control of the network, while the MAC determines the working status of the PHY and controls the PHY by using the SMI (Serial Management Interface) interface to read and write the PHY's registers.Some of the registers in the PHY are defined by IEEE, so that the PHY reflects its current status in the register, and the MAC continuously reads the status register of the PHY through the SMI bus to know the current status of the PHY, such as connection speed, duplex capability, etc.Of course, you can also set the PHY register through SMI to achieve the purpose of control, such as flow-controlled opening and closing, self-negotiation mode or forced mode, etc.

Whether it is the physically connected MII bus and SMI bus, or the status register and control register of the PHY, there are IEEE specifications, so the MAC and PHY of different companies can coordinate their work.Of course, in order to match some of the unique functions of different companies' PHYS, the driver needs to be modified accordingly.

Ebyte Electronic Technology Co., Ltd. specializes in the development and production of wireless data transmission modules with various functions in various frequency bands. The products have been widely used in various application scenarios such as the Internet of Things, consumer electronics, industrial control, medical, smart home, highway, etc. If you have any needs, please contact email:service-es-@cdebyte.com Or visit the website:https://www.es-ebyte.com/

The core of FTTR

EBYTE — Fri, 21 Jul 2023 09:08:10 +0000

fttr, network, connection, signal, transmission, optical fiber, broadband

FTTR (Fiber to the Room) is an advanced network connection technology that transmits the Internet connection directly to each room through optical fiber, providing users with a high-speed and stable network connection.In the traditional network architecture, users need to receive network signals from the computer room downstairs through cables or wireless signal receivers, and then distribute the signals to each room through indoor wiring.FTTR technology transmits network signals directly to each room through optical fiber, providing a more stable and high-speed network experience.

The core of FTTR technology is to install an optical fiber terminal interface (ONT) in each room to connect the optical fiber directly to the user equipment.ONT is a conversion device that converts optical signals transmitted by optical fibers into electrical signals for use by user equipment.Through the high-bandwidth transmission of optical fiber, users can enjoy high-bandwidth services such as high-definition video, online games, and fast downloads at the same time.

**Ebyte Electronic Technology Co., Ltd. specializes in the development and production of wireless data transmission modules with various functions in various frequency bands. The products have been widely used in the Internet of Things, consumer electronics, industrial control, medical care, security alarm, field collection, smart home, highway, property management, water and electricity meter reading, power monitoring, environmental monitoring and other application scenarios. If you have any needs, please contact email:

service-es-@cdebyte.com
Or visit the website:https://www.es-ebyte.com/**

Mobile printers

EBYTE — Mon, 12 Jun 2023 07:35:00 +0000

Mobile printers are very common in our daily work, and the most common ones are logistics label printers in the hands of couriers. This type of mobile printers basically realizes network operation through wireless communication technology. As far as the current market is concerned, Bluetooth occupies a pivotal position in the field of short-distance wireless communication. Bluetooth low energy has the advantages of smart connection, peak current/average current and low current consumption in idle mode, and low cost. The current main smartphones are embedded with Bluetooth Low Energy, which is easy to use, widely used, and popular. Therefore, mobile control based on BLE Bluetooth has gradually become popular in the market.

01
Through the Bluetooth connection between the mobile phone and E104-BT5032A, the documents, pictures and other data on the mobile phone can be directly transmitted to the printing device for printing. E104-BT5032A has the feature of continuous transmission, which can ensure the complete transmission of large files and data, so that users no longer need to rely on PC equipment, no longer need complicated copying and connection, and can print at any time with only a mobile phone.

Feature display
Support the maximum airspeed of 2M, fast transmission speed and short waiting time;
Support multi-master and multi-slave, 4 mobile phones can establish connection with the device at the same time;
Support Bluetooth parameter air configuration function, which is convenient for remote configuration of the device.

02
Every day, Yibyte people are committed to more powerfully assisting the development of IoT, intelligence, and automation, improving resource utilization, and more products and more information. Interested partners can log on to our official website http:// Visit www.ebyte.com to learn more, and the customer service lady will answer questions online!

Talking about the Architecture System of Internet of Things

EBYTE — Tue, 11 Apr 2023 05:57:22 +0000

The challenges posed by the current Internet of Things system have given birth to a new network structure system. Over the past many years, WiFi Wireless Module a large number of standardized frameworks have been designed to solve many challenges and problems faced by the Internet of Things at a large scale.

At present, these frameworks all have the same basic requirement, which is to support the functional requirements of data, processes and terminal devices for execution. The most famous of these are the frameworks defined by oneM2M and the Internet of Things World Forum (IOTWF). Below I will give an in-depth introduction to the two frameworks.

oneM2M IoT standard framework. In the process of standardizing machine-to-machine communication, the European Telecommunications Standards Institute (ETSI) created an association of technical application committees on M2M in 2008. The association was created to create a standard framework to accelerate people's M2M applications and M2M devices. Later, due to the worldwide recognition of the framework, the scope was extended to the field of Internet of Things.

After the M2M Technical Committee established the framework, other organizations also began to lay out the framework of the Internet of Things. In this context, it is indispensable to specify a common M2M standard. After realizing the needs of the market, in 2012, ETSI and its member institutions launched a global initiative to unify the M2M framework. This initiative unifies the global M2M standard, accelerates the development of the Internet of Things Communication efficiency in communication systems and the Internet of Things. The purpose of the initiative is to create a common service layer, which can be directly nested into the device facilities, enabling service communication between devices. These include power grid interconnection, automotive hardware interoperability, industrial equipment health monitoring, intelligent measurement and other equipment interoperability services.

The OneM2M architecture roughly divides the functions of the Internet of Things into three architectures: application layer, service layer and network layer. Although the architecture looks very simple in the literal sense, its performance is very diverse. It not only allows each device to interoperate with each other through calling the IT networking interface, but also supports a large number of new and old IoT devices. technology. Let's take a brief look at these three layers.

Application layer: This layer is mainly concerned with communication between devices. It includes a variety of communication protocols, and attempts to API (interface) the business, and then make the communication change to standardization. Within a specific industry, the application market has its own unique design method and data collection model, so it is shown as different entities in the figure.

Service layer: This layer is the horizontal framework that interconnects industrial applications with the outside world. It includes network, underlying protocols and hardware, etc. Examples include network communication backhaul protocol, MPSL network, VPN, etc. All common based on these is the service layer.

Network layer: This layer is the layer where IoT devices and endpoint devices communicate with each other. It includes the communication between the device itself and the network to which the device is connected. This communication architecture specifically includes a wireless interface and a wireless point-to-multipoint system. At the same time, it also includes the connection between wired devices.

Why do you need a data collector from RS485 to LoRaWAN?

EBYTE — Sun, 29 Jan 2023 08:34:31 +0000

In daily enterprise production, traditional serial devices such as RS485, RS232, RS422 and other interfaces have been widely used, but in actual automated production, it is often necessary to realize data communication of hundreds of meters or even thousands of meters. To realize remote monitoring, it is necessary to Will face these problems:

(1) The communication distance is too far

(2) Scattered data points

(3) The wiring in the networking is too complicated

(4) Wiring is highly restrictive

(5) The problem of line damage often occurs

(6) Difficult to find and repair

When the Internet of Things technology came out, this problem was solved by the RS485 to LoRaWAN data collector. Using LoRa wireless technology and LoRaWAN gateway, the complicated wiring was successfully canceled, and wireless communication replaced wired communication.

The application of ZigBee technology in smart home

EBYTE — Mon, 09 Jan 2023 03:19:30 +0000

Strong anti-interference ability: ZigBee transceiver module uses 2.4G direct-sequence spread spectrum technology, which has better anti-interference ability than general FSK, ASK and frequency hopping data transmission stations.

Good confidentiality: ZigBee provides data integrity check and authentication functions, ZIGBEE Module the encryption algorithm adopts the general AES-128, and the 128-bit password guarantees the confidentiality of ZigBee signal transmission.

Fast transmission speed: ZigBee mostly uses short frames to transmit data, so the transmission speed is fast and the real-time performance is strong.

Strong scalability: ZigBee is easy to network and has strong self-recovery ability. Therefore, it is easy to expand in smart homes and add new devices.

The advantages of zigbee technology looks beautiful

However, we must realize that after many functions of ZigBee are implemented in the application scenarios of smart homes, they become beautiful advantages:

Is the cost of the zigbee module really low?

At present, TI's CC2430, CC2530 and Freescale's MC1319X and MC1322X series, which have relatively large shipments of ZIGBEE chips, cost about 2 to 3 US dollars. Considering other peripheral devices and related 2.4G RF devices, the BOM cost is difficult to be low At $10, serial to ethernet adaptor the cost is quite embarrassing for smart home devices that are cost-sensitive and require a large number of nodes.

Comparison between DSSS and FHSS

EBYTE — Tue, 13 Dec 2022 07:08:52 +0000

Since FHSS systems rely on different RF carrier frequencies, error bursts are mainly due to frequency selective fading.
Error Rate: In DSSS, the information bits are distributed over frequency and time planes, thus minimizing the effects of interference and fading. Therefore, DSSS systems are prone to errors, but at a lower level compared to FHSS systems. FHSS produces strong burst errors.
Although both techniques have errors, it can be seen that the error rate is higher in FHSS than in DSSS systems. Whenever any device approaches the blocking frequency as it hops between channels, the bandwidth of the FHSS system drops.
Compared with DSSS, the decoding process of FHSS is easier. Specific algorithms are required in DSSS to establish the connection between sender and receiver https://www.cdebyte.com/Module-Lora
Network capacity: The transmission rate of DSSS is higher than that of FHSS, DSSS provides a capacity of up to 22 Mbps, while FHSS supports a capacity of up to 3 Mbps.
Reliability: DSSS is more reliable than FHSS systems, which are less reliable in applications. But for mobile applications FHSS is more energy efficient.
Acquisition Time: The time required to convert an analog signal to a digital signal, more in DSSS systems than in FHSS systems.
Cost of use: DSSS is more expensive than FHSS. At lower Mbps (like 2 Mbps), FHSS is less expensive, but generally, radio signals are used at higher Mbps, and DSSS will be cheaper than FHSS.
Application scenarios: In harsh environments, including the presence of large coverage, noise, multipath, and Bluetooth frequency waves, etc., DSSS is ideal for point-to-point applications, while FHSS can be used for point-to-multipoint deployments with excellent performance.