Muliple Slave SPI only one work at the time

Projects Programming
1

Hello,

I got an RC522 RFID reader that work on SPI communication.I implement 4 of them on a protype board.With the same electrical circuit if use a code that active only one antenna at the time it's working.However if i active all of them in the same time (same circuit) only one is working ( the number 2) so i wondering what i am doing wrong.
Thanks for any guidance,my code is bellow

  • Reset 9 5 RST
  • SPI SS 10 53 SDA
  • SPI MOSI 11 51 MOSI
  • SPI MISO 12 50 MISO
  • SPI SCK 13 52 SCK
  • The reader can be found on eBay for around 5 dollars. Search for "mf-rc522" on ebay.com.
    */

#include <SPI.h>
#include <MFRC522.h>

#define SS1_PIN 10
#define RST1_PIN 9
#define SS2_PIN 7
#define RST2_PIN 8
#define SS3_PIN 5
#define RST3_PIN 6
#define SS4_PIN 3
#define RST4_PIN 4

MFRC522 mfrc522_1(SS1_PIN, RST1_PIN); // Create MFRC522 instance.
MFRC522 mfrc522_2(SS2_PIN, RST2_PIN);
MFRC522 mfrc522_3(SS3_PIN, RST3_PIN);
MFRC522 mfrc522_4(SS4_PIN, RST4_PIN);
void setup() {
Serial.begin(9600); // Initialize serial communications with the PC
SPI.begin(); // Init SPI bus
mfrc522_1.PCD_Init(); // Init MFRC522 card
mfrc522_2.PCD_Init();
mfrc522_3.PCD_Init();
mfrc522_4.PCD_Init();
Serial.println("Scan PICC to see UID and type...");
}

void loop() {
// Look for new cards
if ( !mfrc522_1.PICC_IsNewCardPresent()&& !mfrc522_2.PICC_IsNewCardPresent()&& !mfrc522_3.PICC_IsNewCardPresent()&& !mfrc522_4.PICC_IsNewCardPresent()
) {
return;
}

// Select one of the cards
if ( !mfrc522_1.PICC_ReadCardSerial()&&! mfrc522_2.PICC_ReadCardSerial()&&! mfrc522_3.PICC_ReadCardSerial()&&! mfrc522_3.PICC_ReadCardSerial()) {
return;
}
Serial.print(F("<card_uid>"));
dump_byte_array(mfrc522_1.uid.uidByte, mfrc522_1.uid.size);
Serial.print(F("</card_uid><gate_uid>1</gate_uid>"));

Serial.print(F("<card_uid>"));
dump_byte_array(mfrc522_2.uid.uidByte, mfrc522_2.uid.size);
Serial.print(F("</card_uid><gate_uid>2</gate_uid>"));

Serial.print(F("<card_uid>"));
dump_byte_array(mfrc522_3.uid.uidByte, mfrc522_3.uid.size);
Serial.print(F("</card_uid><gate_uid>3</gate_uid>"));

Serial.print(F("<card_uid>"));
dump_byte_array(mfrc522_4.uid.uidByte, mfrc522_4.uid.size);
Serial.print(F("</card_uid><gate_uid>4</gate_uid>"));

// Dump debug info about the card. PICC_HaltA() is automatically called.
mfrc522_1.PICC_DumpToSerial(&(mfrc522_1.uid));
delay(100);

}
void dump_byte_array(byte buffer, byte bufferSize) {
for (byte i = 0; i < bufferSize; i++) {
Serial.print(buffer < 0x10 ? " 0" : " ");
_ Serial.print(buffer, HEX);_
_ }_
_}*_

2

Format your code BEFORE posting and use code tags!.

You can only talk to one SPI dervice at a time.

Mark

3

Sorry didn't know how to format my code or use tag...
Do you meet i can run the Init with only one device at the time ? So i should Init the first one then close it then init the second one and so on ?

Vincent

4

Why not set some flags here if things are present, then talk to the ones that are one at a time?

   // Look for new cards
   if ( !mfrc522_1.PICC_IsNewCardPresent()&& !mfrc522_2.PICC_IsNewCardPresent()&& !mfrc522_3.PICC_IsNewCardPresent()&& !mfrc522_4.PICC_IsNewCardPresent()
) {
      return;
   }