I am trying to read a MIFARE card with MFRC522 shield to open an access door with arduino 2009. Also I have connected an Ethernet shield to detect clients that want to open the access door with an http request and also power on a light. Later on, each event (MIFARE card and/or HTTP request) should be sent to a server.
Now if I put a card near the MFRC522 it open the access door (very good !!!) but ethernet shield doesn't accept http request even if answer to ping request.
If I disconnect MFRC522 shield pins, the HTTP request work fine, I can open access door and power on light.
So, you bought some junk that you don't know how to use. Well, good luck.
and it use pin 9 as SS (you can see in the attached sketch).
That's all that the sketch KNOWS that the shield used. I am NOT willing to accept that those are the ONLY pins the shield uses, in the absence of any manufacturer's information.
the shield use 3.3v,gnd, reset, MOSI, MISO,CLK,SS,
3.3v and ground connected to the arduino 2009 3.3v and ground pins
reset -> arduino pin 8
Mosi -> arduino pin 11
Miso -> arduino pin 12
CLK -> arduino pin 13
SS -> pin 9
do you think is hardware problem ???? I don't understand why the ethernet works stand alone (without the MIFARE powered on) and on the other side the MIFARE works stand alone (if the ethernet cable is not connected)???
No. The reason I wanted to know ALL the pins used was to know how the Mifare shield communicated with the Arduino. Since it uses the SPI pins, that is the means of communication.
The Ethernet shield also uses SPI.
Multiple SPI devices can be connected, as long as two conditions are met:
Each uses a separate CS pin
The libraries involved all use SPI in the same way (speed, bit order, etc.) OR they reset the SPI bus back to default when they are done using the bus.
So, now you need to post a link to the library you are using for the Mifare shield, so we can see if it plays by the rules.
MFRC522 by GithubCommunity Version 20150405.0.0 INSTALLED
Arduino RFID Library for MFRC522 (SPI) read/write a RFID Card or Tag using ISO/IEC 14443A/Mifare interface.