Arduino Ethernet Rev3 without POE - SPI Slave

Hey Guys,

This is my first time using arduino so I’ll try to explain things as well as I can. Please feel free to ask me questions.

So I’m to use the following arduino (https://store.arduino.cc/usa/arduino-ethernet-rev3-without-poe) to do the following:

  1. I want to have the arduino connected to the PC using the RJ45 connector.
  2. I want to connect the arduino to another device, where the arduino will be the slave and the other device will be the master and I also need the clk speed to be 6 MHz. Since the arduino is 16 MHz I’m hoping that won’t be an issue.

The point of this setup is the following:

I want to be able to send data from the PC to the arduino and then have the arduino pass the data to the master device (the master device would have to constantly be passing data to the slave for the slave to pass anyting to the master). So to do this one of the first things I’ll have to do is have the arduino be the slave and have it receive data from the master and send something back. I was hoping to make the the led blink for the time being.

If you have any advice I would appreciate it. Also, the topic for this form is SPI, etc… So if I’m in the wrong form I apologize.

Regards,

Kev.

Hey,

I was wondering if I could use Ethernet and SPI at the same time with arduino ethernet rev3 without poe.

Kev.

Spend some time studying this page:
https://www.arduino.cc/en/Reference/SPI
It does a really good job of explaining things.

You just need to be aware that the Arduino Ethernet uses pin 10 as SS for SPI communication with the W5100 Ethernet controller chip and pin 4 is the SS for the SD card.

AAARGH... cross posting!!!: http://forum.arduino.cc/index.php?topic=510475

  1. I want to connect the arduino to another device, where the arduino will be the slave and the other device will be the master and I also need the clk speed to be 6 MHz. Since the arduino is 16 MHz I'm hoping that won't be an issue.

That is a problem. The maximum frequency the Arduino is able to answer on the SPI bus is 4 MHz because the clock signal has to be in both the HIGH and the LOW state for at least 2 clock cycles according to the datasheet.

So configure that other device to 4MHz SPI or you have to change the project. I'm not aware of any Arduino compatible board that is able to play the slave role on a 6MHz SPI.

Ok. I might be able to get it down to 4 MHz, but just a question. Shouldn’t it work with the arduino tian.

Also my project breakdown:

PC <-(Ethernet)-> Arduino Ethernet Rev3 or Arduino Tian<-(SPI)-> MyDevice <-(Ethernet)-> PC(back to)

So I’ll need to do the following:

  1. Have the arduino of choice in slave mode
  2. I need the PC to pass information to the arduino via Ethernet
  3. My device will be the master and will have to receive the data from the arduino slave (which came from the PC to the arduino) via SPI
  4. My device will take the data do work and send the processed data back to the PC via Ethernet.

Thoughts ?

Shouldn't it work with the arduino tian.

As far as I know the ARM based Arduino platforms are not able to work as an SPI slave.

Thoughts ?

This looks overly complex to me. Why don't you just send that information to "your" device by Ethernet and forget the whole Arduino/SPI stuff? Might be the time to disclose what kind of device that is?

@Kevin111, do not cross-post. Threads merged.