Hi Nick-
I was editing my post as you posted... 
does it matter yours is an ID-12 reader and mine is SPI based?
side questions.. which is much more, beginner "C" question Im guessing..
some noob explanation of ow str[] is getting populated with any data? here in the beginning of the script (loop).. you see this:
***edit: I think I see how ts getting populated eventually, at the end of the MFRC522_ToCard() function call...
how and with what..I havent tried to trace it that closely.. but at least I found that part..
</end edit>
#include <SPI.h>
#define uchar unsigned char
#define uint unsigned int
#define MAX_LEN 16
void loop()
{
uchar i,tmp;
uchar status;
uchar str[MAX_LEN];
uchar RC_size;
uchar blockAddr; //Select operation block address 0 - 63
//Search card, return card types
status = MFRC522_Request(PICC_REQIDL, str);
if (status == MI_OK){
Serial.println("CARD DETECTED IN PROXIMITY....");
Serial.print("CARD TYPE: ");
Serial.print(str[0],DEC);
Serial.print(" / ");
Serial.print("STATUS CODE: ");
Serial.println(str[1],DEC);
//Serial.println(" ");
//delay(500);
}
}
create a var called MAX_LEN = 16
then, to me.. we create a new (empty) array called str[] in the beginning.. it has 16 index/slots long? (based on the str[MAX_LEN] parameter correct? (rule is: you have to give your arrays a length in C, that cant be 'dynamically filled' to whatever amount?)
Im used to be able to do:
var someArray:Array = new Array();
and I can push/populate that to my hearts content (no defining the length prior).. I understand I have been spoiled by this.. but is this correct you must define a length.. (in C)..... (better for memory management I guess?)
here is the function called above, that sets the 'STATUS' var... (again Im curious as to how str[] is being populated.. so I am able to grab the data in each index like in the above snippet)
//MFRC522_Request
//----------------------------------------------------------//
/*
* Function: MFRC522_Request()
* Description: Searching card, read card type
* Input parameter: (reqMode--search methods, TagType--return card types)
* -RETURN CARD TYPE VALUES -
* 0x4400 = Mifare_UltraLight
* 0x0400 = Mifare_One(S50)
* 0x0200 = Mifare_One(S70)
* 0x0800 = Mifare_Pro(X)
* 0x4403 = Mifare_DESFire
* return: return MI_OK (if success)
*/
uchar MFRC522_Request(uchar reqMode, uchar *TagType){
uchar status;
uint backBits; //the data bits that received
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;
}
I see the (empty?) array is passed along to this function, as the second parameter/argument..(as TagType)... (! what does the "" mean in front? !)
then it looks like we are populating index 0 of the str[] array..with the reqMode (parameter we just passed the same function?) value?
from there... Im a bit lost.. seems we call another function (write) and send this array (as the *sendData * *backData arguments of that function?
(posting it here in case it helps?)..
I dont wanna post to much and clutter.. and i dont wanna get too lost either.. (Im trying to understand piece by piece here..LOL)
toCard function:
//MFRC522_ToCard
//----------------------------------------------------------//
/*
* Function: MFRC522_ToCard()
* Description: communicate between RC522 and ISO14443
* Input parameter: (command--MF522 command bits,
sendData--send data to card via rc522,
sendLen--send data length,
backData--the return data from card,
backLen--the length of return data)
*return: return MI_OK (if success)
*/
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: // verify card password
{
irqEn = 0x12;
waitIRq = 0x10;
break;
}
case PCD_TRANSCEIVE: // send data in the FIFO
{
irqEn = 0x77;
waitIRq = 0x30;
break;
}
default:
break;
}
Write_MFRC522(CommIEnReg, irqEn|0x80); //Allow interruption
ClearBitMask(CommIrqReg, 0x80); //Clear all the interrupt bits
SetBitMask(FIFOLevelReg, 0x80); //FlushBuffer=1, FIFO initilizate
Write_MFRC522(CommandReg, PCD_IDLE); //NO action / cancel current command?
for (i=0; i<sendLen; i++){
Write_MFRC522(FIFODataReg, sendData[i]);
}
Write_MFRC522(CommandReg, command);
if (command == PCD_TRANSCEIVE){
SetBitMask(BitFramingReg, 0x80); //StartSend=1,transmission of data starts
}
//wait receive data is finished
i = 2000; //i should adjust according the clock, the maxium the waiting time should be 25 ms???
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 data from 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;
}
Looking at some 'Jeremy Blum' tutorial on-line.. it looks as if the UART version is easier to work with? (shame as I already have this and it was only $20.00)
(my only redemption I have is that every thread/forum/post I have read..everyone to seems to be in the same place as I am with this 'demo code' LOL)
thanks
-xl