Lib-electronic-components similarity-mcu

Use when working with MCU/microcontroller similarity calculations - comparing microcontroller MPNs, understanding family/series/feature matching, or MCU-specific similarity logic.

install

source · Clone the upstream repo

git clone https://github.com/Cantara/lib-electronic-components

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/Cantara/lib-electronic-components "$T" && mkdir -p ~/.claude/skills && cp -r "$T/.claude/skills/similarity-mcu" ~/.claude/skills/cantara-lib-electronic-components-similarity-mcu && rm -rf "$T"

manifest: .claude/skills/similarity-mcu/SKILL.md

source content

MCU Similarity Calculator Skill

Guidance for working with MCU similarity calculators in the lib-electronic-components library.

For metadata-driven similarity architecture, see

/similarity-metadata

SpecImportance levels (CRITICAL, HIGH, MEDIUM, LOW, OPTIONAL)
ToleranceRule types (exactMatch, percentageTolerance, minimumRequired, etc.)
SimilarityProfile contexts (DESIGN_PHASE, REPLACEMENT, COST_OPTIMIZATION, etc.)
Calculator integration patterns and gotchas

Overview

There are two MCU-related calculators:

MCUSimilarityCalculator (Simple Interface)

Implements
```
SimilarityCalculator
```
Uses pattern matching for family/series/features
No PatternRegistry required

MicrocontrollerSimilarityCalculator (Component Interface)

Implements
```
ComponentSimilarityCalculator
```
Uses manufacturer handlers for extraction
Requires PatternRegistry

Applicable Types (MicrocontrollerSimilarityCalculator)

ComponentType.MICROCONTROLLER
ComponentType.MICROCONTROLLER_ATMEL
ComponentType.MICROCONTROLLER_INFINEON
ComponentType.MICROCONTROLLER_ST
ComponentType.MCU_ATMEL

Similarity Weights (MCUSimilarityCalculator)

familySimilarity * 0.5   // Family is most important
seriesSimilarity * 0.3   // Series number
featureSimilarity * 0.2  // Feature codes (F, L, U, etc.)

MCU Families

Family Groups

Group	Members
PIC	PIC16, PIC18, PIC24, PIC32
STM	STM8, STM32
ATM	ATMEGA, ATTINY, ATXMEGA
MSP	MSP430, MSP432

// Same family = 1.0 family similarity
calculator.calculateSimilarity("STM32F103", "STM32F407");
// High similarity (same STM32 family)

// Related family = 0.8 family similarity
calculator.calculateSimilarity("PIC16F877", "PIC18F4550");
// Good similarity (both PIC family)

Feature Codes

Code	Meaning
F	Flash memory
L	Low power
U	USB capable
W	Wireless
R	ROM version
T	Extended temperature

// Same feature codes contribute to similarity
calculator.calculateSimilarity("STM32F103", "STM32F407");
// Both have F (Flash) feature

Series Similarity

Series numbers are compared numerically:

Same series = 1.0
Close numbers (within 100) = partial similarity
Far numbers = lower similarity

// Same series
calculator.calculateSimilarity("ATMEGA328", "ATMEGA328P");
// Very high similarity

// Close series
calculator.calculateSimilarity("ATMEGA328", "ATMEGA329");
// High similarity

// Far series
calculator.calculateSimilarity("ATMEGA328", "ATMEGA2560");
// Lower similarity

MicrocontrollerSimilarityCalculator Scoring

Condition	Score
Same manufacturer, same series, same package	1.0
Same manufacturer, same series, different package	0.9
Official replacement parts	0.8
Same series across manufacturers	0.7
Both microcontrollers, different series	0.5

Test Examples

MCUSimilarityCalculator

// Identical MCU
calculator.calculateSimilarity("ATMEGA328P", "ATMEGA328P");
// Returns 1.0

// Same family, different series
calculator.calculateSimilarity("STM32F103", "STM32F407");
// Returns > 0.5

// Different families
calculator.calculateSimilarity("STM32F103", "ATMEGA328");
// Returns lower similarity

MicrocontrollerSimilarityCalculator

// Same part, different package
calculator.calculateSimilarity("ATMEGA328P-AU", "ATMEGA328P-PU", registry);
// Returns >= 0.5

// Different MCUs
calculator.calculateSimilarity("ATMEGA328P", "STM32F103C8T6", registry);
// Returns 0.5 (base MCU similarity)

Common MCU Patterns

Atmel/Microchip AVR

ATMEGA 328 P -AU
│      │   │  │
│      │   │  └── Package (AU=TQFP)
│      │   └───── Variant (P=Picopower)
│      └───────── Series number
└──────────────── Family

STMicroelectronics STM32

STM32 F 103 C8 T6
│     │ │   │  │
│     │ │   │  └── Package (T6=LQFP48)
│     │ │   └───── Memory/pins
│     │ └───────── Series
│     └─────────── Type (F=Foundation)
└───────────────── Family

Microchip PIC

PIC16 F 877 A
│     │ │   │
│     │ │   └── Variant
│     │ └────── Series
│     └──────── Memory type (F=Flash)
└────────────── Family

Learnings & Quirks

Family Detection

Regex
```
^([A-Z]+)\d+
```
extracts family prefix
Empty family = 0.0 family similarity

Series Number Extraction

Extracts first numeric sequence
Compared as integers for proximity

Feature Code Position

Usually at end of part number
Regex
```
[A-Z]+$
```
extracts trailing letters

Package Codes

Vary significantly by manufacturer
Don't affect core part equivalence
Same MCU in different package = HIGH similarity

Cross-Family Comparison

Different families get Levenshtein similarity
Never returns > 0.8 for different families