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.
1,230
questions
0
votes
1
answer
38
views
Jumper on 100 Mbps Ethernet
Is it possible to pass a 100BASE-TX signal (100 Mbps Ethernet, over 2 differential pairs) through jumpers (one per wire), in order to allow the user to select Ethernet or serial for a given connector?
...
- 7,697
0
votes
1
answer
41
views
10/100 Ethernet PHY: What is this capacitor for?
10/100 Ethernet PHYs such as ENC28J60 and DM9051 recommend the following external components on each pair. What is the circled capacitor for? Any balancing that it provides would seem to be ...
- 409
0
votes
0
answers
46
views
Why does the SPI bus with 2 devices crash in this setup?
I am using Feather M4 express development board with DC Motor + Stepper FeatherWing and Ethernet FeatherWing stacked on it. The idea is to control the steps of the stepper motor by reading the encoder ...
- 153
1
vote
1
answer
26
views
MII to SGMII to connect ETH Switch is it possible?
I want to connect MCU with parallel MII interfaces to switch ICs with SGMII interfaces in this method :
The Eth SW support 8xMDI Channel and 4xSERDES(SGMII,USXGMII,5GBASE-X , ETC).
I'm afraid that I ...
- 441
-1
votes
0
answers
47
views
Make CAN-bus connection as netif interface (LWIP) [closed]
I want make network connection between 2 STM32F407 by CAN-bus protocol (without use physical Ethernet RMII/MII). Could you help me how can i do this? I think I have make CAN connection as netif (...
0
votes
0
answers
21
views
CPU to Switch SGMII port with PCIE 2.5Gb
I can't seem to find a 2.5 Gbps Ethernet controller that could be a bridge between the SGMII+ port and PCIe.
this is what I want to do:
I don't want to use PHY (from the copper 2.5G to 2.5G SGMII)
...
- 441
9
votes
2
answers
818
views
Is there a way to non-destructively test whether an Ethernet cable is pure copper or copper-clad aluminum (CCA)?
I got an Ethernet cable on Amazon for what was, in hindsight, a suspiciously good price. The description says it's copper but one of the one-star reviews claims it's actually copper-clad aluminum (CCA)...
- 91
1
vote
0
answers
30
views
Why does the SJA1105QELY Ethernet Switch chip stop sending packets after it has sent 48,790 bytes
Why does the SJA1105QELY Ethernet Switch chip stop sending packets after it has sent 48,790 bytes?
I designed a circuit card containing the SJA1105 Ethernet Switch made by NXP.
After doing a reset and ...
- 12.4k
4
votes
1
answer
308
views
Can a capacitor be used to close path between center-tap and shield instead of Bob-Smith (capacitor+resistor)?
I believe this has already been quite a controversial topic, but I'm wondering if just a capacitor can be used to direct the common-mode (CM) noise away from the center-taps (CT) of a CM choke back to ...
- 83
4
votes
2
answers
664
views
1000Base-T vs. 100Base-TX captured waveforms and link performance
I have a Gigabit Ethernet port and currently I try to troubleshoot an asymmetry in data throughput.
Doing iperf3 testing I notice that sending is at 900 MBit/s and receiving at 400 MBit/s.
During that ...
- 582
0
votes
1
answer
97
views
Why are common mode chokes used in Ethernet magnetics
I’m trying to understand the reason the common mode choke is required in Ethernet magnetics. To understand, if we look at the schematic, with the common mode choke (horizontal coils) removed, we are ...
- 616
0
votes
2
answers
104
views
High speed data transfer from STM32 to the PC
What is the best way to transfer high-speed data (12.288 Mbit/s) from the STM32H723 microcontroller to a PC? I'm controlling a four-channel audio codec (AK4619vn) and need to sample the FFT of the ...
7
votes
3
answers
260
views
ESD knocking out PHY on device with unisolated POE
I inherited this design, one problem I am having is ESD on the chassis knocks out the PHY, sometimes it can't even be reset via software. I am curious if anyone can spot any glaring errors with the ...
- 84.8k
1
vote
1
answer
49
views
Connecting two W5500 via UDP results in PHY link off
I want to connect two STM32F4 and to communicate via UDP. At the moment I only want to send data from one to another mcu. I have tested tx and rx communication separately with PC - python scripts and ...
- 109
1
vote
0
answers
120
views
Ethernet signal from STM32H7 to LAN8742A good, link good, receive good, no transmit
I am working with a custom board based on the NUCLEO STM32H745. The STM32H745 will receive a broadcast ping and ARP. It will try to respond to the ARP and disregard the broadcast ping. I can trace the ...
- 11