Questions tagged [phy]
The phy tag has no usage guidance.
156
questions
4
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2
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121
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Ethernet PHY - colliding with itself?
I have an embedded system, that whenever the PHY transmits on the twisted pair, the connected hub indicates a collision, and I see nothing on Wireshark. I am 100% confident it is not a software ...
- 101
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vote
1
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33
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Connecting two ethernet PHY's (KSZ8051RNLU) in RMII back toback configuration
I would like to to connect the KSZ8051RNLU in a loopback configuration with itself, I have read that this is possible with other PHY's. Does the KSZ8051RNLU have this capability? Will it auto-...
- 76.2k
0
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1
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74
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Inductor without inductance
I am trying to find the right component for this inductor. It doesn't show inductance which is bit confusing for me. Which part should I pick for this if I wanted to use it on my PCB?
it's from
NUCLEO-...
0
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0
answers
35
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Connection between MCUs with PHY peripherals
I plan to use a MAC TO MAC communication. RMII is decided to be used.
One processor is SAMA5D27 and the other is S32K148.
The signal connections seems to be OK.
But would this configuration work? Also ...
- 787
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1
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39
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PHY 100MBit Link Problem (LAN8814)
We integrated a LAN switch into our design to be able to daisy chain devices and to use PTP. The switch (a LAN9668) has 2 internal CuPhy that we use. It is controlled using an SPI interface and does ...
- 121
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0
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55
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LAN8742a autonegotiation gives a half-duplex mode result when it's espected to be full-duplex mode result
I was testing an ethernet based project PCB that uses LAN8742a xip (lan xip seller link) and a stm32f207zg microcontroller (mcu seller link). We are having some issues when we increase the stress ...
- 787
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0
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28
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ping with lwIP library Xilinx GTR with dp83867 TI PHY
I am working with Xilinx Zynq ultrascale+ , that is built around custom board. In this board I have 3 gems -gem0..gem2 that are connected to DP83867IS PHY.
in addition, my system is working in SGMII , ...
0
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2
answers
152
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PHY address for SPI interface
I'm currently working on a project of a testing module that requires three Ethernet ports:
one for network connection
two for external hardware (one of which is a device being tested)
The testing ...
2
votes
0
answers
102
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ESD problem and how to solve
We have a problem with contact discharge of 3kV on a housing part. The PCB with the PHY are installed in an aluminum lower part with plastic upper part (dimensions approx. 80x80x80mm). The contact ...
user220456
0
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1
answer
66
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High frequency sinks to MOSFET's drain?
I have the following setup on a custom PCB. The WT32-ETH01 module can be normally booted into download/flash mode by holding the IO0 to the GND during the start. The IO0 is also used as a clock ...
- 143
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1
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48
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Merging of Ethernet copper ports into 1
I have configured the copper ports of Ethernet switch as shown below. (i.e merged all the ports and made it has a single port). My understanding is there will be a signal overlap during the Auto-neg ...
user220456
1
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1
answer
181
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MAC to MAC connection TX to RX [duplicate]
I'm connecting two MACs back to back.
One is the IMX6 processor. The other device is this Microchip LAN9370 "5-Port AVB/TSN Gigabit Ethernet Switch with Integrated 100BASE-T1 PHYs".
In that ...
user220456
15
votes
2
answers
2k
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Why are Ethernet MAC and PHY separate?
I’ve been looking for a MCU/MPU with built-in Ethernet connectivity, and I’ve noticed that most only contain a built-in Ethernet MAC interface and require an external PHY.
Why is this the case, as in ...
- 413
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1
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131
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How to build multiport Ethernet switch? [closed]
I have been researching how to build managed/multiport Ethernet switch. There are things that I do not understand and would like to know more.
Some Ethernet switches have built in MACs and if I use ...
- 177
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1
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63
views
How to generate an interrupt on this pin?
In this device, I'm using an internal PHY mode and this pin nPHY_INT is an active-low interrupt output (wrongly mentioned in the datasheet as active-high).
I just want to understand how to generate an ...
user220456
4
votes
2
answers
294
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Adding an extra magnetics transformer for 100Base-T Ethernet
For variuous reasons I need to add an extra transformer between external ethernet connection and an ethernet device that has magnetics built in.
The reason being, among others, to elimnate possible ...
- 171
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1
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32
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Configuration of the Interrupt Signal
I'm using this IC- LAN9500A and want to know how to use pin 1, nPHY_INT.
I'm using internal PHY and want to generate output on this pin 1 (interrupt output)
Can someone tell me how to configure it? Is ...
user220456
1
vote
1
answer
66
views
Meaning of Phase Angle
In this Application Note, section 3.1,
Can someone help me to understand the meaning of "magnitude of phase angle of the load" in simple terms?
Phase angle between Rx and Tx or what does ...
user220456
2
votes
1
answer
208
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Can SGMII MAC communicate with 100BASE PHY at 1 Gb/s?
In the DP83TC811S-Q1 SGMII's datasheet it says
Because the DP83TC811S-Q1 operates at 100 Mbps, the 1.25 Gbps rate of the SGMII is excessive. The SGMII specification allows for 100 Mbps operation by ...
- 57
1
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2
answers
50
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Router: MPU and PHY separate or together?
I'm designing a router and have noticed that some designs use a 'MPU with built in PHY' package on a single chip, whereas others use a PHY IC communicating to a separate CPU/MPU IC over PCIe.
What's ...
- 413
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2
answers
449
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Using an Ethernet gigabit PHY for only 100 and 10 Mbps speeds
I am designing a custom board. I have a USB to Ethernet converter which has 10/100 PHY and I want to connect that PHY to the gigabit Ethernet PHY. I have researched about that problem and found a ...
- 31
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1
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96
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Linking WiFi MCU to Ethernet PHY via PCIe
I'm trying to link this Ethernet PHY to this WiFi 6 MCU via PCIe to make a single port router.
Can I directly connect these two, or do I need some kind of host CPU with two PCIe slots to link them?
...
- 413
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2
answers
1k
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How to use Gigabit Ethernet with MCU?
I am new at ethernet and it comes complex. Trying to use STM32's RMII interface with switch. I just want to see at IT's switch gigabit port. I don't want to transfer data gigabit, it doesn't matter. ...
0
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1
answer
37
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Using ethernet PHY building blocks PAM/PCS
This is a more theoretical question.
Is it possible to use internal building blocks of an Ethernet PHY directly and without typical Ethernet framing?
I am looking for a way to have access to the ...
- 1
2
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2
answers
285
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Ethernet devices polarity reversal support
Does all Ethernet PHY devices support polarity reversal even if its not mentioned in the datasheet?
[I mean polarity reversal by swapping TX+ with TX- (Like connecting TX+ to RX- or TX- to RX+).
Is ...
user220456
1
vote
1
answer
1k
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Ethernet with STM32
I designed an ethernet microchip with reference (LAN8742A-LAN8742) with MCU STM32F767ZGT6, so I followed some document routing ethernet in PCB I respect all rules. when I put the ethernet there is a ...
- 176
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1
answer
441
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Connecting a PHY to another PHY on a same board
I would like to connect voltage-mode PHYs with internal terminations back-to-back.
After doing some research, it looks like simple AC coupling caps can work, but it's better to use a transformer, ...
- 51
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0
answers
50
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Additional processor needed for WiFi-MCU module?
I'm reading up on the design of WiFi-to-Ethernet converters, and came across the Ubiquiti U6-LR Teardown.
I noticed that both this device and its competitors have not just a WiFi-enabled MCU and PHY, ...
- 413
2
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2
answers
334
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What is the voltage at this pin when it is internally pulled high?
I am using a PHY that has internal pull-ups and pull-downs on certain pins.
On this particular pin, there is a pullup that the datasheet says can range from 33 kΩ to 93 kΩ.
For the entire range, I ...
- 189
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1
answer
74
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EEPROM size & Managed Mode vs Unmanaged Mode Ethernet Switch
I want to understand 2 points in Ethernet Switch ICs.
In this IC - LAN9353, on page 34, the description in the table is mentioned.
"A low selects 1K bits (128 x 8) through 16K bits (2K x 8).
A ...
user220456
0
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0
answers
47
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Ethernet PHY MAC Controller - DHCP Request not responding
I am working with this Ethernet PHY.
This is the - MAC Controller IC. I'm using the RMII interface.
When Renesas send the DHCP request, I have the feeling (not 100% sure, I will try to find it out) ...
user220456
1
vote
1
answer
122
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Ethernet PHY RMII waveform without LAN Cable connected
Is the below waveform that I am getting in TX- line of Ethernet (PHY Used - LAN8700) correct? (Waveform obtained without connecting the LAN cable).
Using RMII mode in the PHY. R801 & R803 (pin 1) ...
user220456
2
votes
2
answers
150
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Ethernet differential signals
I've 2 questions on Ethernet design:
Suppose I am using a current mode Ethernet PHY which requires termination resistor of 49.9 ohms to VDD on the Ethernet differential lines.
Can I increase the ...
user220456
0
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1
answer
76
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Question on Resistor and Capacitor Arrangement & Power Supply
I'm using this PHY
My questions:
Is it OK, if I connect 1uF and 1000pF capacitor on the VDDCR pin instead of the recommendation of "1uF & 470pF"? Higher capacitance on the power rail ...
user220456
0
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0
answers
39
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PHY core voltage not proper
I'm using this Ethernet PHY where I'm using an internal regulator for 1V2 by pulling down the LED1/REGOFF Pin.
But few boards are generating 0v9 or 0v8 and few boards are not generating VDDCR Supply ...
user220456
3
votes
3
answers
1k
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Ethernet transformer
Can someone tell me what is the meaning of Open circuit inductance and why we need to take care while choosing magnetics?
Also I have seen that, the turns ratio for selecting magnetics is 1:1 and must ...
user220456
1
vote
1
answer
2k
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Voltage mode Ethernet PHY and Current mode Ethernet PHY
In the Ethernet PHY, we have two types. Voltage mode PHY and current mode PHY.
Can anyone tell me the reason why the center taps of magnetics are shorted in case of connection to a current mode PHY ...
user220456
1
vote
1
answer
96
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What is the impact of different values on the internal capacitor in the magnetics
I am using this connector which has the internal magnetics. I am connecting it to an Ethernet PHY device.
In the datasheet, we can see, that it has internal capacitors of 100nF.
I went through this ...
user220456
0
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0
answers
29
views
What does "No receivers detected" mean for Configuration Link Status?
I'm trying to bringup PCIe, and stuck when trying to link up. Configuration Link Status is 00, which means "No receivers detected", as this document says ...
- 115
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0
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61
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Ethernet Controller - Signals
I was going through the datasheet of this Ethernet controller IC.
I see that the pins are different than that of a Normal Ethernet PHY.
Usually PHY has Ethernet Tx and Rx signals and has the MII/RMII ...
user220456
0
votes
1
answer
43
views
Meaning of Speed and Duplex pin in the IC
In this - Link of the datasheet, can someone tell me what is the meaning/purpose of the DUPLEX Pin and the SPEED pin.
Unable to understand what it actually does and what does it indicate?
user220456
0
votes
1
answer
53
views
What is support for an end-to-end and peer-to-peer transparent clock?
In the datasheet of LAN9353, the description states that it supports "supports end-to-end and peer-to-peer transparent clocks"
Can someone tell me what is the meaning of this?
user220456
0
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0
answers
136
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What is the standard common mode voltage of Media Dependent Interface MDI[0:3]± signals?
I am working on the selection RJ45 connector for MDI interface between PHY and the link-partner.
I am planning to use this PHY for my SGMII interface application. From various online readings, I ...
- 319
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0
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49
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Normal Switch and LAN9353
I am reading about the different types of LAN Switches.
And I came across the LAN9353 device - Link
I want to understand the difference between a normal Gigabit Ethernet 3 port switch and this LAN9353 ...
user220456
-1
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1
answer
69
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Ethernet Switch and QoS Support
I'm going through the Ethernet Switch IC - Link
In the first page, under highlights section, it is mentioned as switch is QoS support.
When I tried to research on what QoS means on this Link, I found ...
user220456
0
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3
answers
432
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Splitting of a differential signal
Can the Ethernet Tx and Rx signals (Using all 4 pairs; RGMII interface) be split into 2 so as to connect to 2 RJ-45 connectors, but only 1 will be used at a time. In general, can we split any ...
user220456
0
votes
1
answer
255
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KSZ8081 PHY address configuration
I'm using this KSZ8081 PHY transceiver.
I'm unable to understand how to configure the PHYAD[0:2] pin and the B-CAST_OFF pin.
As far as I read, the PHY Broadcast address will always be "0" ...
user220456
0
votes
1
answer
179
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Ethernet Switch configuration mode
I'm trying to understand the Ethernet Switch product.
On page 54,55, we can see that, the MAC signals, Like for MII and RMII interface, we can understand that the digital MAC port 3, can be configured ...
user220456
0
votes
1
answer
324
views
RX_ER peripheral not used in RMII
I'm using this PHY and MAC in this Controller
The Controller does not have the ENET_RX_ER peripherals in the 100 pin package.
In that case, can we handle the RX_ER in RMII interface using a GPIO port ...
user220456
0
votes
1
answer
259
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Media Independent Interface
I'm reading about the PHY, MAC and the MII interface.
I understand that the MDI interface from the RJ-45 to PHY will be 10Mbps, 100Mbps or even higher to 1Gbps.
But when this data signals move to the ...
user220456