[FAMILY][SERIES][VARIANT]-[PACKAGE][TEMP]
   │       │        │         │      │
   │       │        │         │      └── Optional temperature grade
   │       │        │         └── Package code (after hyphen)
   │       │        └── Feature variant (P=picopower, A=automotive, etc.)
   │       └── Series number (flash size, pin count encoded)
   └── Product family (ATMEGA, ATTINY, ATSAM, etc.)

ATMEGA328P-PU
│     │  │  ││
│     │  │  │└── (no temp suffix = commercial)
│     │  │  └── U in PU = standard grade
│     │  └── P = picoPower technology
│     └── 328 = 32KB flash, 8-bit
└── ATMEGA = AVR 8-bit megaAVR family

ATSAM3X8E-AU
│    │ ││  ││
│    │ ││  │└── U = standard grade
│    │ ││  └── A = TQFP package
│    │ │└── E = Ethernet variant
│    │ └── 8 = 512KB flash
│    └── 3X = Cortex-M3 SAM3X series
└── ATSAM = ARM-based SAM family

[PACKAGE_TYPE][GRADE]
      │          │
      │          └── U = Standard, C = Commercial, I = Industrial
      └── P=PDIP, A=TQFP, M=QFN, S=SOIC, X=TSSOP, T=QFP, C=WLCSP

ATMEGA328    → Original
ATMEGA328P   → picoPower (lower sleep current)
ATMEGA328PB  → picoPower revision B (more features)
ATMEGA328PA  → Automotive grade picoPower

// Atmel package codes are AFTER the hyphen
// ATMEGA328P-PU → package = "PU"

String[] parts = mpn.split("-");
if (parts.length > 1) {
    String suffix = parts[parts.length - 1];
    return switch (suffix) {
        case "PU" -> "PDIP";
        case "AU" -> "TQFP";
        case "MU" -> "QFN/MLF";
        case "SU" -> "SOIC";
        case "XU" -> "TSSOP";
        case "TU" -> "QFP";
        case "CU" -> "WLCSP";
        default -> suffix;
    };
}

// Extract family + number, stop at variant letter or hyphen
// ATMEGA328P-PU → series = "ATMEGA328"
// ATTINY85-20PU → series = "ATTINY85"

if (mpn.startsWith("ATMEGA")) {
    // Find end of digits after "ATMEGA"
    int end = "ATMEGA".length();
    while (end < mpn.length() && Character.isDigit(mpn.charAt(end))) {
        end++;
    }
    return mpn.substring(0, end);
}

// ATmega: ATMEGA + digits + optional letter variant + optional -package
"^ATMEGA[0-9]+[A-Z]?(?:-[A-Z]{2,4})?$"

// ATtiny: ATTINY + digits + optional variant + optional -package
"^ATTINY[0-9]+[A-Z]?(?:-[A-Z]{2,4})?$"

// SAM: ATSAM + series + variant + -package
"^ATSAM[A-Z0-9]+(?:-[A-Z]{2,4})?$"