2.2.1.2 IEEE EUI-64 Identifier

The IEEE Extended Unique Identifier (EUI) is an 8-byte binary or hexadecimal value, which in this case, is used as a Device EUI to uniquely identify a LoRaWAN node. This globally unique Device EUI (DevEUI) is assigned and written into Slot 10 of the ATECC608A-TNGLoRaWAN. The DevEUI would be part of the reconstructed X.509 Certificate. For the ATECC608A-TNGLoRaWAN the IEEE EUI will be assigned by Microchip.

For the ATECC608A-TNGLoRaWAN, the 8-byte DevEUI is actually stored as a 16-byte ASCII-Hex value. Every digit of the hex EUI byte is represented by an ASCII character equivalent to its hexadecimal numerical value.

EUI-64 Identifier Example

The EUI-64 value is specified as an 8-byte hexadecimal value.
The individual hex digits are interpreted as ASCII characters
Each of these characters are then translated to their actual ASCII hexadecimal code. So an 8-byte hexadecimal value will convert to a 16-byte ASCII-Hex value. Note the conversion between the ASCII character and the ASCII code in both decimal and hexadecimal are shown in Table 2-3.

Table 2-3. Hex to ASCII Conversion
Hex / ASCII Char	ASCII Code		Hex / ASCII Char	ASCII Code
Hex / ASCII Char	DEC	HEX	Hex / ASCII Char	DEC	HEX
“0”	48	0x30	“8”	56	0x38
“1”	49	0x31	“9”	57	0x39
“2”	50	0x32	“A”	65	0x41
“3”	51	0x33	“B”	66	0x42
“4”	52	0x34	“C”	67	0x43
“5”	53	0x35	“D”	68	0x44
“6”	54	0x36	“E”	69	0x45
“7”	55	0x37	“F”	70	0x46

Table 2-4. DevEUI Conversion Example
	Byte 0		Byte 1		Byte 2		Byte 3		Byte 4		Byte 5		Byte 6		Byte 7
ASCII Char	C	B	6	F	D	5	4	B	4	2	3	1	6	6	C	D
ASCII Code(DEC)⁽¹⁾	67	66	54	70	68	53	52	66	52	50	51	49	54	54	67	68
ASCII Code(HEX)⁽¹⁾	43	42	36	46	44	35	34	42	34	32	33	31	36	36	43	44

Note: (1) This is the actual 16-byte value stored in the data slot that represents the IEEE EUI-64 Identifier.