Using an Arduino Mega 2560 and PN532 NFC/RFID module, I want to be able to scan a card and see if its value is (0xF0, 0x21, 0x5D, 0xA7). It should print "accepted"
in the serial monitor.
However during compilation it keeps telling me:
iso14443a_uid:99:11: error: expected primary-expression before ']' token
if (uid[] = {0xF0, 0x21, 0x5D, 0xA7}){
^
exit status 1 expected primary-expression before ']' token
This is my code:
/**************************************************************************/ /*! This example will attempt to connect to an ISO14443A card or tag and retrieve some basic information about it that can be used to determine what type of card it is.
Note that you need the baud rate to be 115200 because we need to print
out the data and read from the card at the same time!
To enable debug message, define DEBUG in PN532/PN532_debug.h
*/
/**************************************************************************/
/* When the number after #if set as 1, it will be switch to SPI Mode*/
#if 0
#include <SPI.h>
#include <PN532_SPI.h>
#include "PN532.h"
PN532_SPI pn532spi(SPI, 10);
PN532 nfc(pn532spi);
/* When the number after #elif set as 1, it will be switch to HSU Mode*/
#elif 0
#include <PN532_HSU.h>
#include <PN532.h>
PN532_HSU pn532hsu(Serial1);
PN532 nfc(pn532hsu);
/* When the number after #if & #elif set as 0, it will be switch to I2C Mode*/
#else
#include <Wire.h>
#include <PN532_I2C.h>
#include <PN532.h>
#include <NfcAdapter.h>
PN532_I2C pn532i2c(Wire);
PN532 nfc(pn532i2c);
#endif
void setup(void) {
Serial.begin(115200);
Serial.println("Hello!");
nfc.begin();
uint32_t versiondata = nfc.getFirmwareVersion();
if (! versiondata) {
Serial.print("Didn't find PN53x board");
while (1); // halt
}
// Got ok data, print it out!
Serial.print("Found chip PN5"); Serial.println((versiondata>>24) & 0xFF, HEX);
Serial.print("Firmware ver. "); Serial.print((versiondata>>16) & 0xFF, DEC);
Serial.print('.'); Serial.println((versiondata>>8) & 0xFF, DEC);
// Set the max number of retry attempts to read from a card
// This prevents us from waiting forever for a card, which is
// the default behaviour of the PN532.
nfc.setPassiveActivationRetries(0xFF);
// configure board to read RFID tags
nfc.SAMConfig();
Serial.println("Waiting for an ISO14443A card");
}
void loop(void) {
boolean success;
uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 }; // Buffer to store the returned UID
uint8_t uidLength; // Length of the UID (4 or 7 bytes depending on ISO14443A card type)
// Wait for an ISO14443A type cards (Mifare, etc.). When one is found
// 'uid' will be populated with the UID, and uidLength will indicate
// if the uid is 4 bytes (Mifare Classic) or 7 bytes (Mifare Ultralight)
success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, &uid[0], &uidLength);
if (success) {
Serial.println("Found a card!");
Serial.print("UID Length: ");Serial.print(uidLength, DEC);Serial.println(" bytes");
Serial.print("UID Value: ");
for (uint8_t i=0; i < uidLength; i++)
{
Serial.print(" 0x");Serial.print(uid[i], HEX);
}
Serial.println("");
// Wait 1 second before continuing
delay(1000);
}
else
{
// PN532 probably timed out waiting for a card
Serial.println("Timed out waiting for a card");
}
if (uid[] = {0xF0, 0x21, 0x5D, 0xA7}){
Serial.println("Success");
}
}
=
is assignment operator. you can't use constant initialization to assign a value to a variable. Inif
condition usually a comparison operator is '==' is used and it can't be used to compare arraysif( uid[0]== 0xF0 && uid[1]==0x21 && ...)
I wanna
in your post .... i have seen a lot of people use it .... i am wondering, how did you learn the wordwanna
? .... it not a word in the English language, by the way ... the statement should beI want to