Questions tagged [ethernet]

Questions about the electrical implementation of Ethernet; ask another Stack Exchange for software or protocol questions. Specify the speed as 10/100BASE-T is somewhat different from 1000BASE-T, apart form the speed. Those are copper standards; Ethernet over fiber optical cable is also defined.

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23 views

ENC28J60 - is this connection correct

Just wondering if this is correct. I never used to design anything using this chip.
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1answer
123 views

Design ethernet switch for multiple devices on pcb?

I'm working on a pcb design with a Raspberry Pi CM module and a microcontroller with ethernet capacity. The goal is to connect the devices to the internet. I'm currently using a normal ethernet ...
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111 views

Adding fiber optic ethernet to a circuit

I'm working on a project that involves transmitting data over very long distances (10-25km) where radio communication is unavailable, and I have been looking into the possibility of adding a fiber ...
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33 views

Media converter - Coax or Twisted Pair [duplicate]

I am working on a Double Leaf Bascule bridge spanning across a river that needs rehabilitated. The bridge is driven from a ControlLogix PLC consisting of 4 racks on the nearside span. Power/control is ...
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53 views

Cat 5e, any gauge?

I am working on a double leaf bascule bridge and installing a PLC I/O rack on the farside. The power transmission between the two piers (nearside and farside) is via a single submarine cable (...
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76 views

Why does 100G Ethernet use FEC while Infiniband doesn't?

The 100G Ethernet physical layer signalling is moving to PAM4 and using Forward Error Correction (FEC) when the lane signalling rate is greater than 25 Gigabaud (Either 4 lanes x 25 or 2 x 50). ...
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107 views

LAN8720A - Reset and Power-up Issues

I am developing a new board that uses an STM32F427 MCU and the LAN8720A as an ethernet PHY. This is my first design with this MCU, but I've done multiple designs with this PHY and other MCUs. I never ...
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116 views

Should I use shielded RJ45 plug by the computers? [closed]

If I have shielded cables, jacks and plugs and I ground the shielding properly, then should I use shielded plugs at the computer's site too? I mean if I do so, then the shielding will be connected to ...
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137 views

Gigabit detection DIY

Ethernet up to 100Mbps uses only 2 of the 4 twisted wires in an ethernet cable while gigabit is using all of them. Connecting an LED to one of the gigabit-only pairs should therefore make it easy to ...
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46 views

Do Broadcom's Ethernet chipsets need special software to operate?

I want to implement an Ethernet switch using Broadcom's chips. Are singing an NDA and getting the datasheets enough to work with the chips? I have heard that the chips must be programmed by a special ...
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124 views

Using only 2 pairs of Ethernet

I'm having a custom cable made that will only use 2 of the 4 pairs for Ethernet. I'm connecting a 10/100 Mbps device to a network with other GigE devices. Pinout is clear: However, I have seen one ...
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92 views

Regarding Current in CAT 5e cable [duplicate]

Can we supply 2A DC current at 5V in the pair of ethernet CAT 5e cable?
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151 views

Broadcom Ethernet PHY link-up issue

We are using BCM5482SA2KFBG PHY for ethernet link in SGMII mode by selecting INTSEL = 2'b10. The PHY was supposed to establish a link upon power up using Autonegotitation without any management ...
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70 views

how to implement Pic18f97j60 with PoE Ethernet

I am a beginner when it comes to mcu and electronics design, I did some projects on Arduino and other ready made microchip boards. However this is my first time building something from scratch. I ...
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41 views

problem connecting an Arduino Ethernet Shield to FPGA trough SPI

I have an Arduino Ethernet Shield and trying to connect it to my spartan 6 board. I used the ICSP header on the bottom of Arduino Ethernet Shield (MISO/SCK/RST/+5/MOSI/GND) and a wire for SS(pin 10 of ...
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68 views

Ethernet magnetics [duplicate]

I am working on a system prototype which includes two ethernet switches (KSZ9896) to provide Ethernet Gigabit connectivity between several devices (let's call them slaves, from now on); every slave ...
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161 views

How to get ip address Schneider PLC controller TM218LDAE40DRPHN? [closed]

I am new to PLC technology and I am doing the following step, listed below: Connect from PLC to retrieve data through Ethernet using Modbus TCP/IP. I found that PLC didn't have its IP address ...
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94 views

Does disconnecting the Tx+ and Tx- wires in the ethernet cable make it Unidirectional for Packet (TCP) sniffing

The DCSW-1005(10/100Base-T) Ethernet switch/TAP can be used as a network TAP (as well as Ethernet switch), in which a copy of outgoing and incoming packets associated with Port 1 (Target port) are ...
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291 views

How to route Ethernet PCB ? [closed]

I am new to PCB routing. In one of my projects, I need to be able to exchange data between nano-computers (https://www.variscite.com/wp-content/uploads/2018/01/DART-6UL_DART-6UL-5G_Datasheet.pdf) ...
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102 views

Divide RS-485 Simply without switch

I have an RS-485 input / output from a solar charge controller (SCC) and would like to read the output in two locations, while maintaining its input from one, or hopefully both of those locations (see ...
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198 views

TVS diodes for Ethernet/PoE?

I am getting confused in selecting TVS diode for Ethernet Interface. Should I connect one bidirectional TVS diode across a ...
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1answer
208 views

Using capacitors for ethernet isolation? [duplicate]

The standard for ethernet says you should use a transformer for isolation. It seems like a cap-based solution would be smaller, more versatile, and a better fit for my application. Is there any ...
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33 views

CC2530: adapting AVR/pgmspace.h for Zigbee

Goal: Adapt ENC28J60 codes written for ATMega328p (http://tuxgraphics.org/electronics/201204/embedded-ethernet-client.shtml) for CC2530. Problem: No equivalent library for AVR/pgmspace.h available ...
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62 views

Connection of LAN8742A nRST pin causes failure when ESD strike

My circuit uses LAN8742A ethernet phy. The system has a metal case and gets 220V AC to power supply board. After converting 5V DC it goes to my board that has Ethernet and mcu. I screwed case and ...
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1answer
239 views

ESD strike breaks the LAN8742A ethernet phy

My circuit uses LAN8742A ethernet phy. The system has a metal case and gets 220V AC to power supply board. After converting 5V DC it goes to my board that has Ethernet and mcu. I screwed case and ...
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1answer
36 views

Interrupt during packet transfer

I'm using the mbed TCP/IP Socket library to receive incoming messages via ethernet. Currently, the incoming data is read in an infinite while(1) loop (i.e. as fast as possible). I will also be ...
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517 views

DP83848 + STM32 & Failed EMC (massive spikes of 25MHz crystal harmonics)

So we've failed EMC two times now because of spikes of 25 MHz harmonics from 175 MHz to 300 MHz, especially 175 MHz, 225 MHz and 275 MHz with peaks easily 30-40 dBuV above noise floor measured with ...
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2answers
82 views

Finding an Ethernet transformer when I have it's characteristics

I am using the Novatel OEM729 board for a project, and I need to implement Ethernet in the project. According to the Novatel OEM7 manual, page 48, the OEM729 does not have Ethernet magnetics, so I ...
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145 views

How does Ethernet to CAN conversion work?

I am wondering how an Ethernet-to-CAN converter works. CAN is a multi-master broadcasting network where messages are associated with IDs. Each message type has a unique ID. Devices listen to all ...
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31 views

ENC28J60 rejects unicast packets - unicast filter is on, MAC is set, and addresses match

I'm programming an ENC28J60 driver at the moment, and have encountered something odd when attempting to receive packets. More specifically, unicast packets. According to the datasheet, when the ...
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1answer
73 views

Power over ethernet and common-mode termination

I have a non-standard Power over Ethernet application (connector, and devices are not ethernet standard but we are using ethernet pairs and protocol for communications). On looking at PoE schematics I ...
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1answer
171 views

Proper connection of choke coil in ethernet magnetics

I need to use the medical ethernet magnetics by Pulse HXU6200NL (it is the only 2MOPP medical-certified PoE magnetics I can find). These are of the rather common transformer/choke coil topology. My ...
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2answers
133 views

Double ethernet magnetics for a passive medical application

I am designing medical data acquisition equipment that requires moderately fast data transfer. As part of the design we are using a custom 100BASE-T PoE architecture (and cabling) to the data ...
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1answer
116 views

How come this non-standard ethernet wiring works?

I am setting up ethernet in a friends house with cat 5 cabling. I do not do this professionally but I have made like 20 patch cables and installed about 20 wall sockets before in my own house. My ...
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1answer
61 views

Designing an PCIe ethernet NIC with built in ethernet switch

I am trying to design a ethernet network card that will plug into a PCIe slot and have 2 etherenet ports visible to the user that are connected by a unmanaged layer 2 switch. My architecture ...
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4answers
2k views

CAT5 for telephony

I wish to extend my incoming telephone connection using CAT5 as I've heard it could provide better performance than standard single stranded telephone wire over long distances. There are only two ...
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1answer
121 views

Ethernet controller not recognized on PCIe bus

I designed a carrier board for this SOM: https://wiki.solid-run.com/doku.php?id=products:ibx:documents As I need a second Ethernet port I added an Intel I217 Ethernet controller. Unfortunately it ...
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155 views

Cable Side and Physical Side of a PoE Magnetics

I am reading the datasheet of PoE Magnetics. I am not able to understand which side belongs to cable side and which belongs to ...
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2answers
311 views

Ethernet switch with 8 ports and PTP [closed]

Hello) I need a solution for a board with 8 100/10 ethernet ports (with copper/fiber switching capabilities, PTP and idealy also with PRP, HSR protocol capabilities). I've found KSZ8999I switch, but I ...
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74 views

Should I model an ethernet message decoder with byte based instead of bit?

The steaming interface (for example the Avalon ST) input logic data[255:0] in_data; // a 256 bits input stream data The local signals of data like this: ...
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2answers
582 views

Using SFP modules from a microcontroller

I'm interested in having an embedded device send data optically. This is for test and measurement, where having conductive cables is problematic since it will perturb the measurement. The device is ...
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1answer
794 views

How can I configure PHY in cubeMX on own board?

I made a customboard using STM32f217VET microcontroller and KSZ8081 PHY (builtin pull-up resistors for TXP TXM and RXP RXM). I Configured my board to use MII mode, anda I used a 25MHz oscillator to do ...
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2answers
621 views

Impedance Matching Resistors on MII Ethernet Lines

Microchip is taking forever to activate my account so I will ask this here... I am using the KSZ8081 PHY for MII Ethernet. https://www.mouser.com/ProductDetail/Microchip-Technology-Micrel/...
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136 views

Can 64b/66b be forced out of DC balance by malicious data?

Unlike 8b/10b and 64b/67b, 64b/66b relies entirely on the scrambler for ensuring DC balance. This raises the question: can a malicious data stream force the line to leave DC balance? Or would it ...
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4answers
174 views

Fiber-optic transceiver ICs for applications other than fiber-optic Ethernet? [closed]

When we talk about fiber-optic transmission, we almost always talk about copper to fiber-optic Ethernet conversion using fiber-optic transceivers. But since fiber-optic communication is just ...
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77 views

Testing Ethernet cable with a signal generator and scope

I have been having some problems with my Ethernet lately and would like to test the cable. I was thinking I could borrow a signal generator and oscilloscope from work and get them hooked up to the ...
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1answer
137 views

1000BASE-T MDI Return Loss Measurement

IEEE 802.3's clause 40.8.3.1 specifies a certain a MDI return loss. The specification states that this return loss shall be maintained at all times when the PHY is transmitting data or control symbols....
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94 views

PHY Register 5 Technology Ability Field Meaning

I have a question about each bit fields(bit 5 to bit 8) of PHY register 5. The following is the description page of a PHY. I know that these fields are Technology Ability Field which is the link-...
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114 views

Inverting REFCLOCK of Ethernet PHY

A few years ago I had to design a board that uses the NXP LPC1769 MCU and had Ethernet connectivity. I was in need of a PHY chip and the LAN8720 was choosen. During design however, I noticed that NXP ...
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1answer
153 views

LAN9500A Ethernet Adapter

I'm designing a USB-to-Ethernet adapter (actually a prototype of a piece of a larger board). As those following my questions will know, I've had some ups and downs getting the USB part working, but ...