LIN Frame Checksum

LIN Checksum Calculator

Calculate Classic or Enhanced LIN bus checksums from hexadecimal data bytes. Enter a LIN frame identifier and payload to generate the protected identifier and final checksum byte.

Classic Checksum Enhanced Checksum LIN PID 1–8 Data Bytes Hex Result

LIN Checksum Classic / Enhanced

Checksum Type Enhanced checksum includes the protected identifier.

LIN Frame ID Enter the 6-bit LIN identifier in hex, from 00 through 3F.

LIN Data Bytes Enter 1 to 8 hexadecimal bytes separated by spaces, such as 10 20 30 40.

Classic checksum sums data bytes only. Enhanced checksum includes the LIN Protected Identifier before the data bytes. Diagnostic frame IDs 0x3C and 0x3D use the Classic checksum rule.

LIN Checksum Result

–

Frame ID –

Protected ID –

Checksum Type –

Checksum –

Checksum Decimal –

Data Length –

Pre-Invert Sum –

Checksum Binary –

Data Bytes –

What Is a LIN Checksum?

LIN, or Local Interconnect Network, uses a checksum byte to help detect errors in the data portion of a LIN frame. The checksum is calculated from the frame data using 8-bit addition with end-around carry, followed by one’s-complement inversion.

Depending on the LIN version and frame type, the calculation may use either the Classic or Enhanced checksum method.

Classic LIN Checksum

The Classic checksum is calculated from the data bytes only. The protected identifier is not included.

Data: 10 20 30 40

Sum: 10 + 20 + 30 + 40
= A0 hex

Checksum: NOT A0
= 5F

Classic checksum behavior is also required for the LIN diagnostic frame identifiers 0x3C and 0x3D.

Enhanced LIN Checksum

The Enhanced checksum adds the protected identifier to the checksum calculation before processing the data bytes.

Enhanced checksum input:

PID + Data Byte 1 + Data Byte 2 + …

Including the protected identifier extends error detection to the frame identifier as well as the payload.

LIN Protected Identifier

A LIN frame identifier contains six identifier bits. Two parity bits are added to create the transmitted 8-bit Protected Identifier, commonly abbreviated PID.

Identifier bits: ID0 ID1 ID2 ID3 ID4 ID5

P0 = ID0 XOR ID1 XOR ID2 XOR ID4

P1 = NOT( ID1 XOR ID3 XOR ID4 XOR ID5 )

The two parity bits occupy bits 6 and 7 of the protected identifier.

LIN Checksum Addition

LIN checksum addition uses end-around carry. When the sum exceeds 255, the carry is added back into the low eight bits.

Example:

F0 + 30 = 120 hex

Low byte: 20

Carry: 1

End-around result: 21

After every required byte has been included, the final eight-bit sum is inverted to produce the checksum.

LIN Checksum Formula

1. Add required bytes

2. Add carry back into low 8 bits

3. Keep final 8-bit sum

4. Checksum = one’s complement of sum

The final checksum therefore always occupies one byte from 00 through FF hexadecimal.

Classic vs Enhanced LIN Checksum

Method	Bytes Included
Classic	Payload data bytes only
Enhanced	Protected Identifier + payload data bytes
Diagnostic IDs 3C / 3D	Classic checksum rule

LIN Data Length

A conventional LIN response can contain up to eight data bytes. Each payload byte contributes to the checksum according to the selected checksum method.

1 byte: A5

4 bytes: 10 20 30 40

8 bytes: 01 02 03 04 05 06 07 08

Why LIN Checksums Are Useful

The checksum provides a lightweight error-detection mechanism for data transferred across a LIN network. A receiving node can perform the same calculation and compare its result with the transmitted checksum byte.

LIN is commonly used in lower-cost embedded and automotive subsystems where a simpler communication network is suitable.

LIN Checksum vs CAN Error Detection

LIN and CAN use different frame structures and error-detection mechanisms. This calculator specifically calculates the LIN response checksum and should not be used for CAN frame CRC calculations.

Important LIN Checksum Notes

Important: this calculator accepts LIN frame identifiers from 0x00 through 0x3F.

The Protected Identifier is generated automatically from the six identifier bits.

Classic checksum includes payload data bytes only.

Enhanced checksum includes the Protected Identifier plus payload data.

Frame identifiers 0x3C and 0x3D use Classic checksum behavior even when Enhanced mode is selected.

Checksum addition uses end-around carry.

The final checksum is the one’s complement of the resulting eight-bit sum.

LIN Checksum Calculator FAQs

What is a LIN checksum?

It is an 8-bit error-detection value calculated from bytes in the LIN response.

What is the difference between Classic and Enhanced LIN checksum?

Classic checksum uses data bytes only. Enhanced checksum also includes the protected identifier.

What is a LIN Protected Identifier?

It is the six-bit LIN identifier combined with two calculated parity bits to form an eight-bit PID.

What range can a LIN frame ID use?

The six-bit identifier field ranges from 0 through 63, or 00 through 3F hexadecimal.

Why are frame IDs 3C and 3D special?

They are diagnostic frame identifiers and use the Classic checksum method.

How many LIN data bytes can I enter?

This calculator accepts between one and eight hexadecimal data bytes.

Does LIN checksum use normal addition?

It uses 8-bit addition with end-around carry, so overflow carry is added back into the low byte.

Is this a LIN CRC calculator?

No. This page calculates the LIN checksum byte used with LIN response data.