Using W5500 without SS pin (just MISO, MOSI, SCK), aka freeing up digital pin 10

I have the Ethernet shield V2 with W5500. I need to free up more pins for my project, so I will be disconnecting the SD SS (slave select) pin and tying it to 5v (or 3.3v if that is more correct) via the resistor to disable it. That frees up Arduino digital pin 4.

Then I want to free up digital pin 10, which is the W5500 SS (slave select) pin since W5500 will be used. I would imagine tying it to ground via the resistor would enable it permanently. Can W5500 work without SS pin control or is it necessary?

yes, it should work. in no SD card is inserted pin 4 is free. the card is the device, without it there is nothing on the pin

The only problem with this is if you want to use multiple SPI devices. The whole point of the CS pin is that it allows you to have multiple SPI devices on the SPI bus. But it sounds like you only are using the one SPI device (W5500).

It is important to note one thing though:
https://www.arduino.cc/en/reference/SPI

Note about Slave Select (SS) pin on AVR based boards
All AVR based boards have an SS pin that is useful when they act as a slave controlled by an external master. Since this library supports only master mode, this pin should be set always as OUTPUT otherwise the SPI interface could be put automatically into slave mode by hardware, rendering the library inoperative.

Juraj:
yes, it should work. in no SD card is inserted pin 4 is free. the card is the device, without it there is nothing on the pin

Huh, okay, sounds like I don't have to move the SMD resistor on pin 4 to disconnect it from the SD circuit. I'll try it without the modification.

pert:
The only problem with this is if you want to use multiple SPI devices. The whole point of the CS pin is that it allows you to have multiple SPI devices on the SPI bus. But it sounds like you only are using the one SPI device (W5500).

It is important to note one thing though:
Arduino - SPI

That's useful info right there. Yeah, I can use that pin as an output so it doesn't interfere with the SPI library. I will have to disconnect it from W5500 though, otherwise there will be unpredictable behavior.

r00tb33r:
Yeah, I can use that pin as an output so it doesn't interfere with the SPI library. I will have to disconnect it from W5500 though, otherwise there will be unpredictable behavior.

bend the pin on shied very little so it doesn't go in the header on Arduino . the pins are usually long so there is enough place for it

Juraj:
bend the pin on shied very little so it doesn't go in the header on Arduino . the pins are usually long so there is enough place for it

I'm stacking a screw terminal/proto shield on top of the W5500 shield, so I actually need that pin to be in the socket. I have no problem moving an SMD resistor over on the board to disconnect SD and W5500 SS signals from the pins. The main question in this thread was whether the W5500 SPI will work without SS control.

Juraj:
bend the pin on shied very little so it doesn't go in the header on Arduino . the pins are usually long so there is enough place for it

I did this just to test if W5500 will work without the SS signal. It appears it does not. I tried connecting unconnected pin 10 on the W5500 shield to ground or to 5V (through the SMD resistor), but example code, like the webserver did not work anymore. I reverted the pin to normal state by bending it back and inserting it into the header, and everything was back to normal.

Is there a modification I have to make to the code to make W5500 SPI work without the SS signal, or is it just not possible? This is the sole question question of this thread.

r00tb33r:
I did this just to test if W5500 will work without the SS signal. It appears it does not. I tried connecting unconnected pin 10 on the W5500 shield to ground or to 5V (through the SMD resistor), but example code, like the webserver did not work anymore. I reverted the pin to normal state by bending it back and inserting it into the header, and everything was back to normal.

Is there a modification I have to make to the code to make W5500 SPI work without the SS signal, or is it just not possible? This is the sole question question of this thread.

a pull-down of CS pin should work.

Juraj:
a pull-down of CS pin should work.

That was my expectation as well, but...

I tried again and bent the pin 10 (W5500 SS) on the Ethernet2 shield so it misses the header and plugged in a 10k resistor between pin 10 of Ethernet2 shield and the GND pin. Ethernet examples don't work after reset. Tried a smaller value a 470 ohm resistor, still doesn't work. Tried just connecting it to GND with a jumper, still same thing.

One observation I made is with pin 10 plugged in to the Arduino header I plugged in an LED (with a resistor of course) between pin 10 and GND and watched it while running Ethernet examples. As you would expect there is activity on that pin when data is exchanged with W5500.

I have a feeling W5500 uses the SS (or CS if you prefer calling it that) signal edges to trigger internal events.

r00tb33r:
That was my expectation as well, but...

I tried again and bent the pin 10 (W5500 SS) on the Ethernet2 shield so it misses the header and plugged in a 10k resistor between pin 10 of Ethernet2 shield and the GND pin. Ethernet examples don't work after reset. Tried a smaller value a 470 ohm resistor, still doesn't work. Tried just connecting it to GND with a jumper, still same thing.

One observation I made is with pin 10 plugged in to the Arduino header I plugged in an LED (with a resistor of course) between pin 10 and GND and watched it while running Ethernet examples. As you would expect there is activity on that pin when data is exchanged with W5500.

I have a feeling W5500 uses the SS (or CS if you prefer calling it that) signal edges to trigger internal events.

sorry, now I remembered