Is it possible to read the ip and mac from PROGMEM (Ethernet)

Projects Programming
1

Hi,

Is it possible to read the ip and mac from PROGMEM?
Ethernet.begin(mac, ip); // where mac and ip come from PROGMEM not from sram.

Thanks for help!

2

Yes.
Have a look at the PROGMEM pages over at the main site and playground

3

Neither the MAC address or the IP address take up much room in SRAM. What is the advantage of moving them to PROGMEM?

Or, are you thinking EEPROM?

4

AWOL:
Yes.
Have a look at the PROGMEM pages over at the main site and playground

I did... i know how to write and read data from/to PROGMEM.
I have no idea how to use it wit the Ethernet.begin() function.

I tried this:

PROGMEM prog_uint8_t mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
Ethernet.begin( { pgm_read_word_near(mac+ 0), pgm_read_word_near(mac+ 1), pgm_read_word_near(mac+ 2), pgm_read_word_near(mac+ 3), pgm_read_word_near(mac+ 4), pgm_read_word_near(mac+ 5) }, ip );
but it doeas not work.

This works great:
Serial.println( pgm_read_word_near(mac+ 0) );
Serial.println( pgm_read_word_near(mac+ 1) );
.
.
.
5

I don't see any overloads of "Ethernet.begin" that takes six "uint8_t"s, just up to four "uint8_t*".
Try reading from PROGMEM into a RAM buffer, then passing that to "Ethernet.begin"