how is a lan card made

[akada]

I am not an electronics guy for some project I want to understand how is a lan card made.
I have read some things (basic) microcontrollers etc but I want to know what exactly is on the lan chip or ethernet controller.I want to know pin connections of lan chip and how it generates ethernet frames.If a timing diagram is available for same that will be great.
Thanks

 

[albert22]

this ethernet controller is used for PIC microcontrollers and arduino. Here you will find the datasheet>
https://ww1.microchip.com/downloads/en/devicedoc/39662a.pdf

 

[HMS1021]

To answer your question would require writing a book on LAN cards.

Just as a overview the LAN card must interface with the differential analog voltages from the Ethernet cable plugged into the RJ-45 connector, recover the digital data, filter the packets with the right address, and put the data on the computers PCI or PCIexpress connector.

PHY
The first step of receiving the data and recovering the digital data is done in the PHY chip. PHY (pronounced fi) is the physical interface. It is connected to the Ethernet cable through a special transformer. The transformer is often built into the RJ-45 connector. The PHY will demodulate the incoming waveform into digital form. The data is sent over the Ethernet cable with extra bits that permit bit error detection and correction. These extra bits are removed and if errors are detected they are corrected leaving the digital data. The data is passed to the MAC. Today, most PHYs will automatically detect if the Tx and Rx wire pairs are switched due to a mis-wired cable or if a cross over cable is used when it is not needed and then automatically make the correct connections.

MAC - Media Access Control
The MAC is where the digital data is reviewed for a address matching the address programmed into the MAC during its configuration. The MAC must be preconfigured so it knows what the packet structure is and which packet will have the address and how many bytes to expect. The structure is different for TCP/IP, IP, UDP and other Ethernet formats. The MAC chip has the transmit and receive buffers (memory) and will often include the PCI, or PCIe, as used on a LAN card. They are also available with many other interfaces to include parallel or simple serial.

There are many devices available that have both the PHY and MAC in the same device. These are often found on LAN cards since it requires fewer chips and reduces cost.
Some MCUs will include a Ethernet MAC and require an external PHY. A few MCUs include both the PHY and MAC. In all case an external transformer must be used.

To gain more information I suggest you review PHY devices first so you can understand the signal interface at the input and the digital format at its output. Once past that review data sheets for combined PHY/MACs. It will make more sense than first reviewing a device that has both the PHY and MAC internal. I have included 3 devices below. You can find their data sheets at digikey or other.



Ti DP83840A PHY (this part is obsolete but it still a good example of a PHY)

MICREL DP83840A (combined PHY / MAC with PCI interface)


MICREL KSZ8851M (Combined PHY and MAC with 8 or 16 bit parallel output)

I hope this is a good start.

 

[akada]

Ti DP83840A PHY (this part is obsolete but it still a good example of a PHY)

MICREL DP83840A (combined PHY / MAC with PCI interface)


MICREL KSZ8851M (Combined PHY and MAC with 8 or 16 bit parallel output)

I hope this is a good start.

Thanks yes this is what I was looking for.