SD card

please , How can i know if the SD card exist in SD card slot or not ?
I want to detect when SD card eject or entered in slot

In the SD card slot on what? Not all SD card reader/writers connect the card detect pin to anything. You'd need to do that if it hasn't been done, and read the pin you connect it to just like any other pin.

Looking at the slot will tell you quite a lot. Failing that, any programme using the SD shopuld have an initialisation test at the start. If a fail message comes up, it is usually because the card isn't there. If it comes up and the card is in the slot, that is just as important to know.

PaulS:
In the SD card slot on what? Not all SD card reader/writers connect the card detect pin to anything. You'd need to do that if it hasn't been done, and read the pin you connect it to just like any other pin.

sorry , i can't understand
How i know if i have detect pin or not and if not how can i make detect pin

did you mean CD pin ?

did you mean CD pin ?

CD as in Card Detect. Yes, that is the one I meant.

PaulS:
CD as in Card Detect. Yes, that is the one I meant.

please, i have another question , can i connect SD shield & RTC (real time clock)Shield with Arduino Due , i mean Arduino Due compatible with SD card & RTC Shield
thanks for your help :smiley:

can i connect SD shield & RTC (real time clock)Shield with Arduino Due , i mean Arduino Due compatible with SD card & RTC Shield

Depends on the shields. If there are no pin conflicts (conflicts seem unlikely), then yes.

PaulS:
Depends on the shields. If there are no pin conflicts (conflicts seem unlikely), then yes.

for SD sheild i use arduino uno and connect pin 11&12&13 and pin 10 for ss slave and i will use arduino due with ICSP-4 & ICSP-1 & ICSP-3 pins and i need to know which pin will connect to ss slave because i don't to know what the diff between SS master & SS slave