please help for the ethernet project

the MagJack is a very good ethernet connector for small projects, it consists of the RJ45 socket, with status LEDs, and the pulse transformer all inside the connector. They eliminate most component sourcing, all you need is the 50E resistances and the inductor.

Yes FvM is technically correct.

Xport is far more complicated than a commonly used MAX232 IC.
In terms of implementation, deploying Xport is quite similar to deploying MAX232.
As a user of Xport, you do not need to worry much about the underlying Ethernet protocol for a start.
You still need to read up about network configuration.

Xport makes these easier for beginner to learn Ethernet.
In fact, it is possible to convert your existing RS232 or RS485 implementation to Ethernet version,
without changing your computer software.

The TCP/IP protocol use in Ethernet is not as complicate as what we find in the text book.
Most of these complicated stuff was already well written in the form of library (or TCP/IP stack)
The higher level Ethernet protocol takes care of a lot of things; unless you are writing the stack then that's a different story.
So as a TCP/IP user, we simply write your code to send the data serially.
How the physical data transmission is done, we do not have to worry to much.
We will learn further more when we encounter a problem.

If you are familiar with MAX232, you will find it easy to use Xport.
Xport was design to make it simple for communicating through Ethernet for those with UASRT/RS232 hardware experience.

siongboon said:

Yes FvM is technically correct.

Xport is far more complicated than a commonly used MAX232 IC.
In terms of implementation, deploying Xport is quite similar to deploying MAX232.
As a user of Xport, you do not need to worry much about the underlying Ethernet protocol for a start.
You still need to read up about network configuration.



Xport makes these easier for beginner to learn Ethernet.
In fact, it is possible to convert your existing RS232 or RS485 implementation to Ethernet version,
without changing your computer software.

The TCP/IP protocol use in Ethernet is not as complicate as what we find in the text book.
Most of these complicated stuff was already well written in the form of library (or TCP/IP stack)
The higher level Ethernet protocol takes care of a lot of things; unless you are writing the stack then that's a different story.
So as a TCP/IP user, we simply write your code to send the data serially.
How the physical data transmission is done, we do not have to worry to much.
We will learn further more when we encounter a problem.

If you are familiar with MAX232, you will find it easy to use Xport.
Xport was design to make it simple for communicating through Ethernet for those with UASRT/RS232 hardware experience.

Click to expand...

thanks for the information ....

hi i have attached schematic of my single board computer (SBC) using ethernet protocol for communication between pc and communication board and also i attached block diagram of SBC.
the working of SBC is as below:

Objective is to design and develop an application specific Single Board Computer (SBC). The major task is to monitor and control the various sub modules present in the microwave power module (MPM), at the same time it has to communicate with the computer (pc) by sending status of the MPM and receiving the commands through a serial communication link. It behaves like a line front end communication module which can support multiple communication protocols like RS485/CAN/ ETHERNET etc.
The communication with SMC can be done by three different protocols.
1. Rs485.
2. CAN protocol
3. Ethernet protocol.

pic controller: In the proposed design we are going to use a low end microcontroller since this SBC is not performing any complex functions. The main task of the controller is to act as a communication interface between different protocols. Along with that it has to read the temperature sensor output for the temperature measurement and the IREM output to detect the presence of RF in TWT output.

Buffers: All the signals which are input and output from the surge board are passed through a buffer before passing it to the microcontroller.

Optocoupler: These are the digital optocoupler which are used for providing the isolation between the EPC board and the SBC.

LED Indications: These are used for the indicating the RX, TX, UART line status by blinking the LED's. An optional feature is provided to indicate the modes of operation of the MPM.

this is my project details ..i have not implemented it.. please go though schematic and guide me to improve schematic or any mistakes in schematic or any safty measures... hope will get good feedback...

thank you...

and also i don't how to choose RBAIS resistor value, please help me determine its value.
thank you....

please help me to calculate rbais value...

Reference PIC18F97J60 Datasheet, pg 219, Section 19.1.4 MAGNETICS, TERMINATION AND OTHER EXTERNAL COMPONENTS

PIC18F97J60 Family Data Sheet

The internal analog circuitry in the PHY module requires
that an external resistor (2.26 kΩ) be attached from
RBIAS to ground. The resistor influences the TPOUT+/-
signal amplitude. It should be placed as close as possible
to the chip with no immediately adjacent signal traces to
prevent noise capacitively coupling into the pin and
affecting the transmit behavior. It is recommended that
the resistor be a surface mount type.

Click to expand...

Surface Mount 2.26KΩ

This should take care of your RBIAS resistor value.

BigDog

please go though schematic and guide me to improve schematic or any mistakes in schematic or any safety measures...

Click to expand...

I fear, there's a lot of detail faults, and unfortunately I'm sure, that I'll be able to identify only a few of them without spending hours to review the schematics.

For the ethernet PHY/transformer/media part, I suggest to read thorougly datasheet figure 18-2. You'll notice that TX requires a power supply, that's missing in your circuit. As said, it also answers the Rbias question. The difference in termination of unused cable pairs isn't that important, but it actually serves a purpose to provide 75 ohms common mode termination.

Also, the 25 MHz crystal won't work with 15 nF capacitors.

I wonder, if you are hiding the GND node name for VSS pins, or if they are unconncted.

FvM said:

I fear, there's a lot of detail faults, and unfortunately I'm sure, that I'll be able to identify only a few of them without spending hours to review the schematics.

For the ethernet PHY/transformer/media part, I suggest to read thorougly datasheet figure 18-2. You'll notice that TX requires a power supply, that's missing in your circuit. As said, it also answers the Rbias question. The difference in termination of unused cable pairs isn't that important, but it actually serves a purpose to provide 75 ohms common mode termination.

Also, the 25 MHz crystal won't work with 15 nF capacitors.

I wonder, if you are hiding the GND node name for VSS pins, or if they are unconncted.

Click to expand...

i have changed lot in schematic and i'll upload by tomorrow..thank you.

lokesh88 said:

i have changed lot in schematic and i'll upload by tomorrow..thank you.

Click to expand...

but in datasheet they mentioned for 25MHZ , 15nF cap is used...on what basis did u told it won't work.please explain or provide any link related to it..
thank you...

i have changed my schematic and uploaded again please check it once...

but in datasheet they mentioned for 25MHZ , 15nF cap is used

Click to expand...

No MHz crystal would work with 15 nF. In my datasheet, I see 33 pF (Chapter 2.3 Crystal Oscillator, Table 2.1)

sorry i have not uploaded schematic...here it is...

FvM said:

No MHz crystal would work with 15 nF. In my datasheet, I see 33 pF (Chapter 2.3 Crystal Oscillator, Table 2.1)

Click to expand...

will check once....

It's the same version of Aug-11-2011, that you posted yesterday. Apart from the said 15 nF capacitor, I didn't identify any issues yet.

FvM said:

It's the same version of Aug-11-2011, that you posted yesterday. Apart from the said 15 nF capacitor, I didn't identify any issues yet.

Click to expand...

no i have connected 3.3v supply to tout pin and also i have changed in UART signals..earlier i have used 4 UART signals and in latest version i have used 2 signals...

Schematic from post#24 is different, post #31 and #33 are identical...