Questions tagged [phy]
The phy tag has no usage guidance.
171 questions
0
votes
0
answers
67
views
What is the difference between the PHY sublayers PCS, PMA and PMD?
I'm reading Analog Device's Beginner's Guide to Ethernet. It's really good and goes into concepts like Manchester Encoding, 4B/5B, NRZT, MLT3 which seem to make sense to me. However, it kind of ...
- 2,086
-1
votes
1
answer
34
views
spreading factor in LoRa PHY (CSS)
I wonder how the spreading factor (SF) is defined in LoRa PHY.
Specifically, in other spread spectrum techniques (e.g DS, FH), we have:
W = R * SF
W is the (spread) bandwidth, and R is the symbol rate....
- 31
0
votes
1
answer
64
views
KSZ8081RNA PHY Design
I am designing a circuit using the KSZ8081RNAIA Ethernet PHY, and I have a question regarding the use of pin 23 (LED pin). The datasheet can be found here.
As I understand it, pin 23 is a strap-in pin ...
- 377
1
vote
2
answers
129
views
Ethernet 1G Magnetic swap is possible?
I have the following circuit with Ethernet switch that connect to quad magnetic, my layout engineer required me to swap for easier layout. Pay attention - the swap will be only in the magnetic side, ...
- 471
3
votes
2
answers
919
views
What does it mean to write to the Register of an IC?
I am interested in using DP83TD510E as an ethernet PHY (side note, it seems to be one of the only ones I can find that supports 10Base-T-10L) and don't understand how it could be "programmed"...
- 31
1
vote
1
answer
137
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
1
answer
251
views
How can I configure RealTek RTL8211F for 100Base-T?
Introduction
I'm planning to use RealTek RTL8211F Ethernet PHY.
I have an example schematic.
Problem
The problem here is that the RJ45 Ethernet connector 48F-01GYDXNL is very difficult to get and I'm ...
- 1,388
1
vote
1
answer
227
views
LAN8720 MDC (SMI Clock) and/or ringing issue
I had always difficult times with designs having LAN8720 device on it. It behaves differently with each design (this is understandable and even I carefully design it according to the design ...
- 283
1
vote
1
answer
247
views
Ethernet PHY design query: Compatibility of DP83848QSQ/NOPB with STM32F407VET6 and pin configuration concerns
I'm relatively new to Ethernet PHY design and currently working on a project where I've chosen the DP83848QSQ/NOPB PHY and plan to connect it to the STM32F407VET6 microcontroller.
However, I've ...
user362241
2
votes
5
answers
252
views
Ethernet PHY and their corresponding hardware are represented Right to Left in most datasheets and application notes schematic. Why?
What's the matter?
If you are here for complicated applied physics, you'll be quite disappointed. This post is just about a bit of electronic world trivia.
I am currently designing a board with two ...
- 173
1
vote
1
answer
311
views
LAN8720A - PoE Protection
I will go straight to my question.
I have currently a PoE PD using LAN8720A PHY,
i follow almost all manufacturer recommendations on PCB layout and schematics, anyways i have dead LAN8720A straight ...
- 23
0
votes
2
answers
217
views
Do we need differential routing TX and RX in Ethernet RMII MAC to MAC Connection
I am implementing an Ethernet mac to mac connection between SAMA5D27C-D1G-CU and FS32K148UJT0VLQT micro-controller.
In MAC to MAC communication PHY TX is connected to RX of MAC and vice versa as shown ...
- 3,061
0
votes
2
answers
118
views
Ethernet switch
I'm designing a PCB and it requires me to receive three Ethernet ports, and output one of them to the forth port. Then it goes from Ethernet to a USB converter, and goes to the system.
My question is, ...
1
vote
2
answers
466
views
Ethernet Magnetics Polarity Swapping
Can I on the same pair (for Example A) to swap polarity on opposite side of transformer/magnetics?
Update 1: Currently i use cross-over method to make lanes shorted and more easy to layout.
Update 2:...
- 23
0
votes
1
answer
184
views
Termination of unused MDI pairs
I'm muxing Ethernet MDI between two PHYs – one of which is 10/100 (2-pair) and the other of which is 1+Gbps (4-pair). A single set of magnetics (4-pair) serves both PHYs via the mux. Does anybody have ...
- 167
-1
votes
1
answer
379
views
How to define PHY mode and MAC mode between back to back switches
I'm planning to use this Switch IC connected to another another switch ic which is the same part number. When connecting these devices in back to back mode with RGMII interface between then, I need to ...
- 945
4
votes
2
answers
247
views
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 ...
- 183
1
vote
1
answer
133
views
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-...
- 88.8k
0
votes
1
answer
80
views
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
votes
0
answers
142
views
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 ...
- 945
1
vote
1
answer
94
views
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
1
vote
0
answers
187
views
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 ...
- 871
0
votes
2
answers
536
views
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
177
views
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
votes
1
answer
81
views
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 ...
- 173
0
votes
1
answer
50
views
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
vote
1
answer
379
views
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
16
votes
2
answers
4k
views
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 ...
- 425
0
votes
1
answer
612
views
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
0
votes
1
answer
91
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
508
views
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 ...
- 181
0
votes
1
answer
34
views
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
83
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
391
views
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
vote
2
answers
69
views
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 ...
- 425
2
votes
2
answers
1k
views
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
1
vote
1
answer
174
views
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?
...
- 425
0
votes
2
answers
3k
views
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
votes
1
answer
51
views
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
votes
2
answers
1k
views
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
3k
views
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
5
votes
1
answer
2k
views
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
0
votes
0
answers
55
views
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, ...
- 425
2
votes
2
answers
429
views
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 ...
- 215
1
vote
1
answer
110
views
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
votes
0
answers
68
views
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
181
views
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
321
views
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
votes
1
answer
153
views
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
votes
0
answers
44
views
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