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UDS Hex File Programming Example ​

This example demonstrates how to program a hex file into an ECU using UDS (Unified Diagnostic Services) protocol. The project shows how to use HexMemoryMap to parse a hex file and program it into an ECU using block transfer.

Overview ​

The example implements a programming sequence using the following UDS services:

  • RequestDownload (0x34)
  • TransferData (0x36)
  • RequestTransferExit (0x37)

Tester Config ​

Tester (tester.ts) ​

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Service ​

  • 0x34
  • 0x36
  • 0x37

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Sequence ​

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tester.ts Implementation Details ​

HexMemoryMap Usage ​

The project uses HexMemoryMap to parse an Intel HEX file:

typescript
const hexFile = path.join(process.env.PROJECT_ROOT, 'Hello_World.hex')
const hexStr = await fsP.readFile(hexFile, 'utf8')
const map = HexMemoryMap.fromHex(hexStr)
// Convert hex data into memory blocks
for(const [addr, data] of map) {
pendingBlocks.push({addr, data})
}

More details about HexMemoryMap can be found in the API documentation.

Programming Flow ​

The programming process is divided into two main job functions:

Job Function 0 (Initial Request) ​

  • Reads the next memory block to be programmed
  • Sends RequestDownload (0x34) service with memory address and size
  • Gets maximum block size from ECU response
typescript
const r34 = DiagRequest.from("Tester.RequestDownload520")
const memoryAddress = Buffer.alloc(4)
memoryAddress.writeUInt32BE(currentBlock.addr)
r34.diagSetParameterRaw('memoryAddress', memoryAddress)
r34.diagSetParameter('memorySize', currentBlock.data.length)

Job Function 1 (Data Transfer) ​

  • Splits data into chunks based on maxChunkSize
  • Sends TransferData (0x36) for each chunk
  • Sends RequestTransferExit (0x37) after all chunks
  • Restarts process if more blocks exist

Key Features ​

  1. Dynamic Block Size Adjustment

    • Adjusts block size based on ECU capabilities
    • Aligns to 8-byte boundaries for optimal transfer
    typescript
    maxChunkSize -= 2 // Account for block sequence counter
if (maxChunkSize & 0x07) {
    maxChunkSize -= (maxChunkSize & 0x07)
}

  2. Block Sequence Counter

    • Implements 1-255 rolling counter for block tracking
    typescript
    const blockSequenceCounter = Buffer.alloc(1)
blockSequenceCounter.writeUInt8((i + 1) & 0xFF)

  3. Automatic Block Management

    • Queues multiple memory blocks
    • Handles transitions between blocks automatically
    • Restarts programming sequence for each block

Flow Diagram ​

ECU Simulation ​

Node 1(ecu.ts) simulation that responds to the programming requests. The ECU side handles three main services: alt text

1. RequestDownload (0x34) Response ​

typescript
Util.On('Tester.RequestDownload520.send', async (req) => {
    const resp = DiagResponse.fromDiagRequest(req)
    // Response: 0x74 (positive response)
    // 0x40: length format identifier
    // 0x00000081: maxNumberOfBlockLength (129 bytes)
    resp.diagSetRaw(Buffer.from([0x74, 0x40, 0, 0, 0, 0x81]))
    await resp.outputDiag()
})
  • Responds with positive response (0x74)
  • Specifies maximum block length (129 bytes)
  • Uses length format identifier 0x40

2. TransferData (0x36) Response ​

typescript
Util.On('Tester.TransferData540.send', async (req) => {
    const resp = DiagResponse.fromDiagRequest(req)
    // Response: 0x76 (positive response) + block sequence counter
    resp.diagSetRaw(Buffer.from([0x76, Number(req.diagGetParameter('blockSequenceCounter'))]))
    await resp.outputDiag()
})
  • Acknowledges each data block with positive response (0x76)
  • Echoes back the block sequence counter
  • Simulates successful data transfer

3. RequestTransferExit (0x37) Response ​

typescript
Util.On('Tester.RequestTransferExit550.send', async (req) => {
    const resp = DiagResponse.fromDiagRequest(req)
    // Response: 0x77 (positive response)
    resp.diagSetRaw(Buffer.from([0x77]))
    await resp.outputDiag()
})
  • Confirms completion of transfer with positive response (0x77)
  • Simulates successful programming completion

The ECU simulation provides a complete test environment for the programming sequence, allowing developers to test their programming implementation without actual hardware.

Demo ​

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