Bonjour,

je suis étudiant ingénieur en systèmes embarqués et mon projet consiste en la réalisation d'un lecteur de badge RFID. J'ai acheté un lecteur RC522 que j'ai connecté à mon arduino ( en attendant de recevoir la véritable carte de projet MBED) via le port SPI. J'ai trouvé le code sur internet que j'ai modifié un peu par moi même et tout fonctionne parfaitement ! Le lecteur reconnait le badge et la carte Mifare et emet un bip de reconnaissance grâce à un buzzer.
Voila la datasheet du RC522: http://www.nxp.com/documents/data_sheet/MFRC522.pdf

Ainsi que le code:
Code : Sélectionner tout - Visualiser dans une fenêtre à part
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
/*
 * File Name : RFID.pde
 * Creator : Dr.Leong (WWW.B2CQSHOP.COM)
 * Create Date: 2011.09.19
 * Modified by :
 * Modify Date:
 * Chinese comments translated using Google Translate by
 * Description : Mifare1 -> find cards - > Anti-collision - > Select Card - > reader interface
 */
// the sensor communicates using SPI, so include the library:
#include <SPI.h>
#include<Servo.h>
 
#define	uchar	unsigned char
#define	uint	unsigned int
 
// Maximum length of the array
#define MAX_LEN 16
 
/////////////////////////////////////////////////////////////////////
//set the pin
/////////////////////////////////////////////////////////////////////
const int chipSelectPin = 10;
const int NRSTPD = 5;
 
//MF522 command word
#define PCD_IDLE              0x00               //NO action; cancel the current command
#define PCD_AUTHENT           0x0E               // authentication key
#define PCD_RECEIVE           0x08               // receive data
#define PCD_TRANSMIT          0x04               // Transmit Data
#define PCD_TRANSCEIVE        0x0C               // Send and receive data
#define PCD_RESETPHASE        0x0F               // Reset
#define PCD_CALCCRC           0x03               // CRC calculation
 
//Mifare_One card command word
#define PICC_REQIDL           0x26               // find the antenna area does not enter hibernation
#define PICC_REQALL           0x52               // find all the cards antenna area
#define PICC_ANTICOLL         0x93               // anti-collision
#define PICC_SElECTTAG        0x93               // election card
#define PICC_AUTHENT1A        0x60               // authentication key A
#define PICC_AUTHENT1B        0x61               // authentication key B
#define PICC_READ             0x30               // Read Block
#define PICC_WRITE            0xA0               // write block
#define PICC_DECREMENT        0xC0               // debit?
#define PICC_INCREMENT        0xC1               // recharge?
#define PICC_RESTORE          0xC2               // transfer block data to the buffer
#define PICC_TRANSFER         0xB0               // save the data in the buffer
#define PICC_HALT             0x50               // Sleep
 
 
//和MF522 communication error code is returned when
#define MI_OK                 0
#define MI_NOTAGERR           1
#define MI_ERR                2
 
 
//------------------MFRC522 register---------------
//Page 0:Command and Status
#define     Reserved00            0x00
#define     CommandReg            0x01
#define     CommIEnReg            0x02
#define     DivlEnReg             0x03
#define     CommIrqReg            0x04
#define     DivIrqReg             0x05
#define     ErrorReg              0x06
#define     Status1Reg            0x07
#define     Status2Reg            0x08
#define     FIFODataReg           0x09
#define     FIFOLevelReg          0x0A
#define     WaterLevelReg         0x0B
#define     ControlReg            0x0C
#define     BitFramingReg         0x0D
#define     CollReg               0x0E
#define     Reserved01            0x0F
//Page 1:Command
#define     Reserved10            0x10
#define     ModeReg               0x11
#define     TxModeReg             0x12
#define     RxModeReg             0x13
#define     TxControlReg          0x14
#define     TxAutoReg             0x15
#define     TxSelReg              0x16
#define     RxSelReg              0x17
#define     RxThresholdReg        0x18
#define     DemodReg              0x19
#define     Reserved11            0x1A
#define     Reserved12            0x1B
#define     MifareReg             0x1C
#define     Reserved13            0x1D
#define     Reserved14            0x1E
#define     SerialSpeedReg        0x1F
//Page 2:CFG
#define     Reserved20            0x20
#define     CRCResultRegM         0x21
#define     CRCResultRegL         0x22
#define     Reserved21            0x23
#define     ModWidthReg           0x24
#define     Reserved22            0x25
#define     RFCfgReg              0x26
#define     GsNReg                0x27
#define     CWGsPReg	          0x28
#define     ModGsPReg             0x29
#define     TModeReg              0x2A
#define     TPrescalerReg         0x2B
#define     TReloadRegH           0x2C
#define     TReloadRegL           0x2D
#define     TCounterValueRegH     0x2E
#define     TCounterValueRegL     0x2F
//Page 3:TestRegister
#define     Reserved30            0x30
#define     TestSel1Reg           0x31
#define     TestSel2Reg           0x32
#define     TestPinEnReg          0x33
#define     TestPinValueReg       0x34
#define     TestBusReg            0x35
#define     AutoTestReg           0x36
#define     VersionReg            0x37
#define     AnalogTestReg         0x38
#define     TestDAC1Reg           0x39
#define     TestDAC2Reg           0x3A
#define     TestADCReg            0x3B
#define     Reserved31            0x3C
#define     Reserved32            0x3D
#define     Reserved33            0x3E
#define     Reserved34			  0x3F
//-----------------------------------------------
Servo myServo;
//4 bytes card serial number , the first 5 bytes for the checksum byte
uchar serNum[5];
 
uchar  writeData[16]={0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 100};  // Initialize 100 dollars
uchar  moneyConsume = 18 ;  // spending 18 yuan
uchar  moneyAdd = 10 ;  // recharge 10 yuan
// Sector A password , 16 sectors , each sector password 6Byte
uchar sectorKeyA[16][16] = {{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
//{0x19, 0x84, 0x07, 0x15, 0x76, 0x14},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
};
uchar sectorNewKeyA[16][16] = {{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xff,0x07,0x80,0x69, 0x19,0x84,0x07,0x15,0x76,0x14},
//you can set another ket , such as  " 0x19, 0x84, 0x07, 0x15, 0x76, 0x14 "
//{0x19, 0x84, 0x07, 0x15, 0x76, 0x14, 0xff,0x07,0x80,0x69, 0x19,0x84,0x07,0x15,0x76,0x14},
// but when loop, please set the  sectorKeyA, the same key, so that RFID module can read the card
{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xff,0x07,0x80,0x69, 0x19,0x33,0x07,0x15,0x34,0x14},
};
 
void setup() {
    myServo.attach(9);
    Serial.begin(9600);                       // RFID reader SOUT pin connected to Serial RX pin at 2400bps
    Serial.println("Ready");
 
    // start the SPI library:
    SPI.begin();
 
    pinMode(chipSelectPin,OUTPUT);             // Set digital pin 10 as OUTPUT to connect it to the RFID /ENABLE pin
    digitalWrite(chipSelectPin, LOW);          // Activate the RFID reader
    pinMode(NRSTPD,OUTPUT);               // Set digital pin 10 , Not Reset and Power-down
    digitalWrite(NRSTPD, HIGH);
 
    MFRC522_Init();
}
 
void loop()
{
    uchar i,tmp;
    uchar status;
    uchar str[MAX_LEN];
    uchar RC_size;
    uchar blockAddr;	// select the operating block addresses 0 to 63
 
 
    // Find the card , back card type
    status = MFRC522_Request(PICC_REQIDL, str);	// trouve la carte
    /*if (status == MI_OK)
     * {
     * Serial.println("Find out a card ");
     * Serial.print(str[0],BIN);
     * Serial.print(" , ");
     * Serial.print(str[1],BIN);
     * Serial.println(" ");
     * }*/
    status = MFRC522_Anticoll(str);   // lit le numéro de série de la carte // Anti-collision, return card serial number 4 bytes
    memcpy(serNum, str, 5);   // copie des 5 octets de str vers serNum
    if (status == MI_OK)
    {
 
        /*Serial.println("The card's number is  : ");
         * Serial.print(serNum[0]);     // ajouter, BIN pour avoir en binaire
         * Serial.print(" , ");
         * Serial.print(serNum[1]);
         * Serial.print(" , ");
         * Serial.print(serNum[2]);
         * Serial.print(" , ");
         * Serial.print(serNum[3]);
         * Serial.print(" , ");
         * Serial.print(serNum[4]);
         * Serial.println(" ");*/
    }
    if (serNum[0]==111 && serNum[1]==173 && serNum[2]==35 && serNum[3]==29 && serNum[4]==252 )
    {
        Serial.println(" Bonjour Sebastien ");
        Serial.println(" Vous pouvez entrer ");
        tone (8, 400, 400);
        delay (500);
        myServo.write(180);
        delay (4000);
        myServo.write(0);
    }
    if (serNum[0]==132 && serNum[1]==210 && serNum[2]==114 && serNum[3]==26 && serNum[4]==62 )
    {
        Serial.println(" Bonjour Monsieur !");
        Serial.println(" Tu peux aussi entrer ");
        tone (8, 400, 400);
        delay (500);
        myServo.write(180);
        delay (4000);
        myServo.write(0);
 
    }
}
 
 
 
 
 
/*
 * Function Name : Write_MFRC5200
 * Description: MFRC522 of a register to write a byte of data
 * Input Parameters : addr - register address ; val - the value to be written
 * Return value: None
 */
 
// page 11 -> MSB=BLPS
// 1=read ; 0=write
// LSB=0
void Write_MFRC522(uchar addr, uchar val)
{
    digitalWrite(chipSelectPin, LOW); //actif
 
    // Addresse au Format :0XXXXXX0
    addr=addr<<1;  // on souhaite un 0 en BLMS, on décale donc addr de 1 bit vers la gauche pour ne perdre aucune informations (p11)
    addr=addr&0x7E;  //afin d'avoir BLPS=0 pour écrire
    SPI.transfer(addr);  // ou sinon addr=(addr<<1)&0x7E
    SPI.transfer(val);  // ecriture de la valeur
    digitalWrite(chipSelectPin, HIGH); //inactif
}
 
 
/*
 * Function Name : Read_MFRC522
 * Description : From a certain MFRC522 read a byte of data register
 * Input Parameters : addr - register address
 * Return value : Returns a byte of data read from the
 */
uchar Read_MFRC522(uchar addr)
{
    uchar val;
 
    digitalWrite(chipSelectPin, LOW);  // actif
 
    // Addresse au Format : 1XXXXXX0 afin de pouvoir lire
    addr=addr<<1;  // on souhaite un 0 en BLMS, on décale donc addr de 1 bit vers la gauche pour ne perdre aucune informations (p11)
    addr=addr|0x80;  //afin d'avoir BLPS=1 pour lire
    SPI.transfer(addr); // ou sinon SPI.transfer(((addr<<1)&0x7E) | 0x80);
    val =SPI.transfer(0x00);  // envoit du BLPS p10
 
    digitalWrite(chipSelectPin, HIGH);   //inactif
 
    return val;
}
 
/*
 * Function Name : SetBitMask
 * Description: Set RC522 register bit
 * Input parameters : reg - register address ; mask - set value
 * Return value: None
 */
void SetBitMask(uchar reg, uchar mask)    // a voir
{
    uchar tmp;
    tmp = Read_MFRC522(reg);
    Write_MFRC522(reg, tmp | mask);  // set bit mask
}
 
 
/*
 * Function Name : ClearBitMask
 * Description : clear RC522 register bit
 * Input parameters : reg - register address ; mask - clear bit value
 * Return value: None
 */
void ClearBitMask(uchar reg, uchar mask)  // a voir
{
    uchar tmp;
    tmp = Read_MFRC522(reg);
    Write_MFRC522(reg, tmp & (~mask));  // clear bit mask
}
 
 
/*
 * Function Name : AntennaOn
 * Description : Open antennas, each time you start or shut down the natural barrier between the transmitter should be at least 1ms interval
 * Input: None
 * Return value: None
 */
void AntennaOn(void)
{
    uchar temp;
 
    temp = Read_MFRC522(TxControlReg);
    if (!(temp & 0x03))
    {
        SetBitMask(TxControlReg, 0x03);
    }
}
 
 
/*
 * Function Name : AntennaOff
 * Description : Close antennas, each time you start or shut down the natural barrier between the transmitter should be at least 1ms interval
 * Input: None
 * Return value: None
 * /
 */
void AntennaOff(void)
{
    ClearBitMask(TxControlReg, 0x03);
}
 
 
/*
 * Function Name : ResetMFRC522
 * Description : Reset RC522
 * Input: None
 * Return value: None
 */
void MFRC522_Reset(void)
{
    Write_MFRC522(CommandReg, PCD_RESETPHASE);
    //CommandReg 0x01   starts and stops command execution
}
 
 
/*
 * Function Name : InitMFRC522
 * Description : Initialize RC522
 * Input: None
 * Return value: None
 */
void MFRC522_Init(void)
{
    digitalWrite(NRSTPD,HIGH);
 
    MFRC522_Reset();
 
    //Timer: TPrescaler*TreloadVal/6.78MHz = 24ms
    Write_MFRC522(TModeReg, 0x8D);		//Tauto=1; f(Timer) = 6.78MHz/TPreScaler   p53
    Write_MFRC522(TPrescalerReg, 0x3E);	//TModeReg[3..0] + TPrescalerReg
    Write_MFRC522(TReloadRegL, 30);
    Write_MFRC522(TReloadRegH, 0);
 
    Write_MFRC522(TxAutoReg, 0x40);		//100%ASK
    Write_MFRC522(ModeReg, 0x3D);		//CRC初始值0x6363	???
 
    //ClearBitMask(Status2Reg, 0x08);		//MFCrypto1On=0
    //Write_MFRC522(RxSelReg, 0x86);		//RxWait = RxSelReg[5..0]
    //Write_MFRC522(RFCfgReg, 0x7F);   		//RxGain = 48dB
 
    AntennaOn();		//打开天线
}
 
 
/*
 * Function Name : MFRC522_Request
 * Description : Find cards , read the card type number
 * Input parameters : reqMode - find cards way
 * TagType - Return Card Type
 * 0x4400 = Mifare_UltraLight
 * 0x0400 = Mifare_One (S50)
 * 0x0200 = Mifare_One (S70)
 * 0x0800 = Mifare_Pro (X)
 * 0x4403 = Mifare_DESFire
 * Return value: the successful return MI_OK
 */
uchar MFRC522_Request(uchar reqMode, uchar *TagType)   // trouve la carte et identifie le numéro du type de carte
{
    uchar status;
    uint backBits;			// received data bits
 
    Write_MFRC522(BitFramingReg, 0x07);		//TxLastBists = BitFramingReg[2..0]	???
 
    TagType[0] = reqMode;
    status = MFRC522_ToCard(PCD_TRANSCEIVE, TagType, 1, TagType, &backBits);
 
    if ((status != MI_OK) || (backBits != 0x10))
    {
        status = MI_ERR;
    }
 
    return status;
}
 
 
/*
 * Function Name : MFRC522_ToCard
 * Description : RC522 and ISO14443 card communication
 * Input Parameters : command - MF522 command word,
 * SendData - RC522 sent to the card via the data
 * SendLen - length of data sent
 * BackData - received the card returns data,
 * BackLen - return data bit length
 * Return value: the successful return MI_OK
 */
uchar MFRC522_ToCard(uchar command, uchar *sendData, uchar sendLen, uchar *backData, uint *backLen)
{
    uchar status = MI_ERR;
    uchar irqEn = 0x00;
    uchar waitIRq = 0x00;
    uchar lastBits;
    uchar n;
    uint i;
 
    switch (command)
    {
        case PCD_AUTHENT:		// certification cards close   if command=PCD_AUTHENT   0x0E               // authentication key
        {
            irqEn = 0x12;
            waitIRq = 0x10;
            break;
        }
        case PCD_TRANSCEIVE:	 // transmit FIFO data    if command=PCD_TRANSCEIVE   0x0C               // Send and receive data
        {
            irqEn = 0x77;
            waitIRq = 0x30;
            break;
        }
        default:
            break;
    }
 
    Write_MFRC522(CommIEnReg, irqEn|0x80);	// enable interrupt request
    ClearBitMask(CommIrqReg, 0x80);			// clear all interrupt request bit
    SetBitMask(FIFOLevelReg, 0x80);			// FlushBuffer = 1, FIFO initialization
 
    Write_MFRC522(CommandReg, PCD_IDLE);	// NO action; cancel the current command ? ? ?
 
    // Write data to the FIFO
    for (i=0; i<sendLen; i++)
    {
        Write_MFRC522(FIFODataReg, sendData[i]);
    }
 
    // Execute the command
    Write_MFRC522(CommandReg, command);
    if (command == PCD_TRANSCEIVE)
    {
        SetBitMask(BitFramingReg, 0x80);		//StartSend=1,transmission of data starts
    }
 
    // Wait for completion of receiving data
    i = 2000; // i according to the clock frequency adjustment , the operator M1 card maximum waiting time 25ms???
    do
    {
        //CommIrqReg[7..0]
        //Set1 TxIRq RxIRq IdleIRq HiAlerIRq LoAlertIRq ErrIRq TimerIRq
        n = Read_MFRC522(CommIrqReg);
        i--;
    }
    while ((i!=0) && !(n&0x01) && !(n&waitIRq));
 
    ClearBitMask(BitFramingReg, 0x80);			//StartSend=0
 
    if (i != 0)
    {
        if(!(Read_MFRC522(ErrorReg) & 0x1B))	//BufferOvfl Collerr CRCErr ProtecolErr
        {
            status = MI_OK;
            if (n & irqEn & 0x01)
            {
                status = MI_NOTAGERR;			//??
            }
 
            if (command == PCD_TRANSCEIVE)
            {
                n = Read_MFRC522(FIFOLevelReg);
                lastBits = Read_MFRC522(ControlReg) & 0x07;
                if (lastBits)
                {
                    *backLen = (n-1)*8 + lastBits;
                }
                else
                {
                    *backLen = n*8;
                }
 
                if (n == 0)
                {
                    n = 1;
                }
                if (n > MAX_LEN)
                {
                    n = MAX_LEN;
                }
 
                // Read the received data in FIFO
                for (i=0; i<n; i++)
                {
                    backData[i] = Read_MFRC522(FIFODataReg);
                }
            }
        }
        else
        {
            status = MI_ERR;
        }
 
    }
 
    //SetBitMask(ControlReg,0x80);           //timer stops
    //Write_MFRC522(CommandReg, PCD_IDLE);
 
    return status;
}
 
 
/*
 * Function Name : MFRC522_Anticoll
 * Description : Anti- collision detection , reading selected card serial number card
 * Input parameters : serNum - returns 4 bytes card serial number , the first 5 bytes for the checksum byte
 * Return value: the successful return MI_OK
 */
uchar MFRC522_Anticoll(uchar *serNum)
{
    uchar status;
    uchar i;
    uchar serNumCheck=0;
    uint unLen;
 
 
    //ClearBitMask(Status2Reg, 0x08);		//TempSensclear
    //ClearBitMask(CollReg,0x80);			//ValuesAfterColl
    Write_MFRC522(BitFramingReg, 0x00);		//TxLastBists = BitFramingReg[2..0]
 
    serNum[0] = PICC_ANTICOLL;
    serNum[1] = 0x20;
    status = MFRC522_ToCard(PCD_TRANSCEIVE, serNum, 2, serNum, &unLen);
 
    if (status == MI_OK)
    {
        // Check Card Serial Number
        for (i=0; i<4; i++)
        {
            serNumCheck ^= serNum[i];
        }
        if (serNumCheck != serNum[i])
        {
            status = MI_ERR;
        }
    }
 
    //SetBitMask(CollReg, 0x80);		//ValuesAfterColl=1
 
    return status;
}
 
 
/*
 * Function Name : CalulateCRC
 * Description: CRC calculation with MF522
 * Input parameters : pIndata - To read the CRC data , len - the data length , pOutData - CRC calculation results
 * Return value: None
 */
void CalulateCRC(uchar *pIndata, uchar len, uchar *pOutData)
{
    uchar i, n;
 
    ClearBitMask(DivIrqReg, 0x04);			//CRCIrq = 0
    SetBitMask(FIFOLevelReg, 0x80);			//清FIFO指针
    //Write_MFRC522(CommandReg, PCD_IDLE);
 
    // Write data to the FIFO
    for (i=0; i<len; i++)
    {
        Write_MFRC522(FIFODataReg, *(pIndata+i));
    }
    Write_MFRC522(CommandReg, PCD_CALCCRC);
 
    // Read the CRC calculation result
    i = 0xFF;
    do
    {
        n = Read_MFRC522(DivIrqReg);
        i--;
    }
    while ((i!=0) && !(n&0x04));			//CRCIrq = 1
 
    // Read the CRC calculation result
    pOutData[0] = Read_MFRC522(CRCResultRegL);
    pOutData[1] = Read_MFRC522(CRCResultRegM);
}
 
 
/*
 * Function Name : MFRC522_SelectTag
 * Description: election card , read the card memory capacity
 * Input parameters : serNum - Incoming card serial number
 * Return value: the successful return of card capacity
 */
uchar MFRC522_SelectTag(uchar *serNum)
{
    uchar i;
    uchar status;
    uchar size;
    uint recvBits;
    uchar buffer[9];
 
    //ClearBitMask(Status2Reg, 0x08);			//MFCrypto1On=0
 
    buffer[0] = PICC_SElECTTAG;
    buffer[1] = 0x70;
    for (i=0; i<5; i++)
    {
        buffer[i+2] = *(serNum+i);
    }
    CalulateCRC(buffer, 7, &buffer[7]);		//??
    status = MFRC522_ToCard(PCD_TRANSCEIVE, buffer, 9, buffer, &recvBits);
 
    if ((status == MI_OK) && (recvBits == 0x18))
    {
        size = buffer[0];
    }
    else
    {
        size = 0;
    }
 
    return size;
}
 
 
/*
 * Function Name : MFRC522_Auth
 * Description : Verify card password
 * Input parameters : authMode - Password Authentication Mode
 * 0x60 = A key authentication
 * 0x61 = B key authentication
 * BlockAddr - block address
 * Sectorkey - Sector password
 * serNum - card serial number, 4-byte
 * Return value: the successful return MI_OK
 */
uchar MFRC522_Auth(uchar authMode, uchar BlockAddr, uchar *Sectorkey, uchar *serNum)
{
    uchar status;
    uint recvBits;
    uchar i;
    uchar buff[12];
 
    // Validate instruction block address + sector + password + card serial number
    buff[0] = authMode;
    buff[1] = BlockAddr;
    for (i=0; i<6; i++)
    {
        buff[i+2] = *(Sectorkey+i);
    }
    for (i=0; i<4; i++)
    {
        buff[i+8] = *(serNum+i);
    }
    status = MFRC522_ToCard(PCD_AUTHENT, buff, 12, buff, &recvBits);
 
    if ((status != MI_OK) || (!(Read_MFRC522(Status2Reg) & 0x08)))
    {
        status = MI_ERR;
    }
 
    return status;
}
 
 
/*
 * Function Name : MFRC522_Read
 * Description : Read block data
 * Input parameters : blockAddr - block address ; recvData - read block data
 * Return value: the successful return MI_OK
 */
uchar MFRC522_Read(uchar blockAddr, uchar *recvData)
{
    uchar status;
    uint unLen;
 
    recvData[0] = PICC_READ;
    recvData[1] = blockAddr;
    CalulateCRC(recvData,2, &recvData[2]);
    status = MFRC522_ToCard(PCD_TRANSCEIVE, recvData, 4, recvData, &unLen);
 
    if ((status != MI_OK) || (unLen != 0x90))
    {
        status = MI_ERR;
    }
 
    return status;
}
 
 
/*
 * Function Name : MFRC522_Write
 * Description : Write block data
 * Input parameters : blockAddr - block address ; writeData - to 16-byte data block write
 * Return value: the successful return MI_OK
 */
uchar MFRC522_Write(uchar blockAddr, uchar *writeData)
{
    uchar status;
    uint recvBits;
    uchar i;
    uchar buff[18];
 
    buff[0] = PICC_WRITE;
    buff[1] = blockAddr;
    CalulateCRC(buff, 2, &buff[2]);
    status = MFRC522_ToCard(PCD_TRANSCEIVE, buff, 4, buff, &recvBits);
 
    if ((status != MI_OK) || (recvBits != 4) || ((buff[0] & 0x0F) != 0x0A))
    {
        status = MI_ERR;
    }
 
    if (status == MI_OK)
    {
        for (i=0; i<16; i++)		//向FIFO写16Byte数据
        {
            buff[i] = *(writeData+i);
        }
        CalulateCRC(buff, 16, &buff[16]);
        status = MFRC522_ToCard(PCD_TRANSCEIVE, buff, 18, buff, &recvBits);
 
        if ((status != MI_OK) || (recvBits != 4) || ((buff[0] & 0x0F) != 0x0A))
        {
            status = MI_ERR;
        }
    }
 
    return status;
}
 
 
/*
 * Function Name : MFRC522_Halt
 * Description : Command card into hibernation
 * Input: None
 * Return value: None
 */
void MFRC522_Halt(void)
{
    uchar status;
    uint unLen;
    uchar buff[4];
 
    buff[0] = PICC_HALT;
    buff[1] = 0;
    CalulateCRC(buff, 2, &buff[2]);
 
    status = MFRC522_ToCard(PCD_TRANSCEIVE, buff, 4, buff,&unLen);
}
Cependant le code utilisé me parait relativement compliqué et j'ai beaucoup de mal à le comprendre d'ou l'objet de mon post. Après quelques bonnes heures passés dessus, j'ai compris l'intégralité de quelques fonctions notamment
" Write_MFRC522" et "Read_MFRC522" ainsi que certains bouts de code par ci par la.
J'ai pas mal étudié la datasheet du lecteur RC522 et par exemple, je ne comprend pas la fonction

"MFRC522_ToCard", je sais qu'elle identifie la norme ISO14443 et qu'elle l'applique sur le badge, enfin c'est ce que j'ai compris... Mais concrètement dans cette fonction qu'est ce qu'il se passe ?

En espérant avoir quelques réponses ou des éléments de réponses qui pourront me faire avancer, je vous remercie d'avance