/* Four bytes of eeprom at 0x20 are purchase year & month in BCD format, with 16bit
* complemented checksum; e.g. 2004DFFB = 2020-April.
* This helps to identify the age of devices if unknown magic numbers occur.
/* Four bytes of eeprom at 0x20 are purchase year & month in BCD format, with 16bit
* complemented checksum; e.g. 2004DFFB = 2020-April.
* This helps to identify the age of devices if unknown magic numbers occur.