Which one is SS

Hey guys for one of my projects i have to use ultiple SPI devices at ghe same time and i know i have to seperate SS pins but i do not know which o e is SS like on nRF24L01 there is 8 pins called GND VCC CE CS MOSI MISO SCK and IRQ which pin is SS

It should be CS. Check on each device to insure that pin is active LOW.

I do not get it why it should be LOW

Normally SPI libraries expect the SS pin to be active LOW, and disabled HIGH. Insure you disable all SPI devices before initializing any SPI device.

So you mean at the setup section i have to disable all SS pins by digitalWrite(SS_PIN, HIGH);

NewStudent: So you mean at the setup section i have to disable all SS pins by digitalWrite(SS_PIN, HIGH);

Yes.

After disabling them should i activate them again

NewStudent:
After disabling them should i activate them again

Conditionally no. If you are going to write your own access code, then you would need to manipulate the slave selects. If you are using existing libraries, they will take care of the slave selects for you.

I want to use rc522 with sdcard reader and i am goinv to use like 50 diffrent cards and every cards uid will be stored in sd card so while reading data from rc522 rfid module should i disable sd cards ss pin and while reading and writing to sd card should i disable rc522

NewStudent: Hey guys for one of my projects i have to use ultiple SPI devices at ghe same time and i know i have to seperate SS pins but i do not know which o e is SS like on nRF24L01 there is 8 pins called GND VCC CE CS MOSI MISO SCK and IRQ which pin is SS

With SPI bus some say SlaveSelect and some say CableSelect meaning the same thing.

So they use either the abbreviation SS( SlaveSelect) or CS( Cable Select) and the pin labeled CS is what you are looking for.