RequestDownload / TransferData / TransferExit

#!/usr/bin/env python3
# 0x34 RequestDownload: declare block to program
import udsoncan, struct
from udsoncan.client import Client

def request_download(client, start_addr: int, length: int,
                     compression: int = 0x00, encrypting: int = 0x00) -> int:
    # dataFormatIdentifier: high nibble = compression, low nibble = encryption
    dfi = (compression << 4) | encrypting

    # memoryAddressAndLengthFormatIdentifier: 0x44 = 4-byte address, 4-byte length
    memloc = udsoncan.MemoryLocation(
        address=start_addr,
        memorysize=length,
        address_format=32,
        memorysize_format=32
    )

    resp = client.request_download(dfi, memloc)
    if not resp.positive:
        raise Exception(f"RequestDownload failed: NRC 0x{resp.code:02X}")

    # ECU responds with maxNumberOfBlockLength (max bytes per TransferData block)
    max_block_len = resp.service_data.max_block_length
    print(f"RequestDownload OK: max block length = {max_block_len} bytes")
    return max_block_len

# Example:
# max_block = request_download(client, 0x80080000, 0x00780000)  # 7.5 MB application block
# NRC 0x31 (requestOutOfRange): address/size not matching any configured block
# NRC 0x33 (securityAccessDenied): Level 2 not unlocked

#!/usr/bin/env python3
# 0x36 TransferData: send firmware in blocks
import udsoncan, math
from pathlib import Path

def transfer_firmware(client, image_path: str, max_block_len: int):
    image = Path(image_path).read_bytes()
    total_size = len(image)
    block_size = max_block_len - 2  # subtract 0x36 SID + sequence byte overhead

    num_blocks = math.ceil(total_size / block_size)
    print(f"Transferring {total_size:,} bytes in {num_blocks} blocks "
          f"of {block_size} bytes each")

    for seq in range(1, num_blocks + 1):
        offset = (seq - 1) * block_size
        chunk  = image[offset : offset + block_size]

        resp = client.transfer_data(seq & 0xFF, chunk)  # sequence wraps 0x00–0xFF
        if not resp.positive:
            raise Exception(f"TransferData block {seq} failed: NRC 0x{resp.code:02X}")

        # Progress
        pct = (seq / num_blocks) * 100
        print(f"  Block {seq}/{num_blocks} ({pct:.0f}%) — {len(chunk)} bytes", end="
")

        # NRC 0x71 (transferDataSuspended): ECU ran out of buffer; retry after delay
        # NRC 0x72 (generalProgrammingFailure): flash write error; abort programming

    print(f"
Transfer complete: {total_size:,} bytes sent")