place mac to SRAM instead of flash

[nagimov]

This example doesn't work when mac is placed to flash (using nano v3 with old bootloader)

[nuno-silva]

Indeed, ether.begin seems to assume macaddr is in RAM:

EtherCard/src/EtherCard.cpp

Lines 31 to 38 in 420dd84

	uint8_t EtherCard::begin (const uint16_t size,
	const uint8_t* macaddr,
	uint8_t csPin) {
	using_dhcp = false;
	#if ETHERCARD_STASH
	Stash::initMap();
	#endif
	copyMac(mymac, macaddr);

EtherCard/src/webutil.cpp

Lines 13 to 15 in 420dd84

	void EtherCard::copyMac (uint8_t *dst, const uint8_t *src) {
	memcpy(dst, src, ETH_LEN);
	}

Perhaps it would be best to overload ether.begin with support for passing a MAC in PROGMEM, but at least this makes it work for now...

[nagimov]

@nuno-silva
Yes if it could be implemented similarly to dnsLookup and accept optional fromRam flag that would be ideal:

EtherCard/src/dns.cpp

Line 91 in 420dd84

bool EtherCard::dnsLookup (const char* name, bool fromRam) {

[nuno-silva]

No need for an additional argument :)
It just needs to be overloaded to receive const __FlashStringHelper* instead of const uint8_t*, like this:

https://github.com/arduino/ArduinoCore-avr/blob/3055c1efa3c6980c864f661e6c8cc5d5ac773af4/cores/arduino/Print.cpp#L44-L55

The overloaded begin method would just need to read the uint8_t array from flash to a temporary buffer in the stack/RAM and call the regular const uint8_t* method. It's also possible to avoid the temporary array by "copy pasting" the regular method and changing the memcpy call to a loop reading from flash :)

[nuno-silva]

I could implemented it, but I have no setup to test it at the moment.

[nagimov]

Better solution is in #398