Experimental sketch, testing storing a MAC address in program memory and casting to __FlashStringHelper

FlashStringTest.ino

// Experimental sketch, testing storing a MAC address in program memory and casting to __FlashStringHelper
// By Nicholas Humfrey

// This Macro isn't available for AVR architecture in the Arduino IDE
#ifndef FPSTR
#define FPSTR(pstr_pointer) (reinterpret_cast<const __FlashStringHelper *>(pstr_pointer))
#endif

const static byte mymac[] = { 0x74, 0x69, 0x69, 0x2D, 0x30, 0x31 };
const static byte myprogmac[] PROGMEM = { 0x74, 0x69, 0x69, 0x2D, 0x30, 0x31 };

// Function to print a MAC address stored in RAM
int printMac(const byte *mac)
{
    for (int i = 0; i < 6; i++) {
        Serial.print(mac[i], HEX);
        if (i < 5)
            Serial.print(':');
    }
    Serial.println();
}

// Function to print a MAC address stored in program memory
int printMac(const __FlashStringHelper *mac)
{
    byte ramBytes[6];
    // Copy the string from flash program memory into RAM
    memcpy_P(ramBytes, (const void *)mac, 6);
    printMac(ramBytes);
}


void setup ()
{
    Serial.begin(57600);
    Serial.println("[FlashStringTest]");

    // Print MAC address stored in RAM
    //printMac(mymac);

    // Print MAC address from an inline string stored in programme memory
    //printMac(F("\x74\x69\x69\x2D\x30\x31"));

    // Print Mac address stored in programme memory using the FPSTR() macro
    printMac(FPSTR(myprogmac));
}

void loop ()
{

}