Luca
c32c4645b5
Tooling and findings for running an E8x/E9x electric power steering unit
outside its donor car, e.g. in an EV conversion.
Headline result: the EPS needs only two CAN messages plus a 12V enable
wire, not the 69-message set the car puts on the bus:
0x130 CAS terminal status (100ms) brings the unit up
0x1A0 DSC road speed (20ms) sets the assist level
Total required rate is 60 frames/s. Protocol write-up, including what is
proven vs. inferred and the open questions, is in eps-comms/.
Contents:
adapters/ CANdapter (its SLCAN dialect differs) and generic SLCAN
gateway/ car<->EPS relay, replay, message bench, EPS controller,
4-tab Streamlit UI
decoder/ PT-CAN frame decoding and live/replay sources
can-io/ XIAO ESP32-S3 firmware: CAN IO board + USB-CAN bridge with
a CAN-independent digital IO channel
tools/ capture, bitrate scan, startup-order and session analysis,
checksum solver
captures/ reference working session + the replay set eps_control reads
59 lines
2 KiB
Python
59 lines
2 KiB
Python
"""Extract the CAN-IO board's own digital IO timeline (IN1-4/OUT1-2) from a
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gateway session log, by pulling out its status frames (arbitration ID
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0x100, see can-io/PROTOCOL.md) - the board sends one immediately on any
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input/output change plus a 1s heartbeat, so this recovers when each
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channel was high/low over the session (at that resolution - a change that
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gets undone within a couple of debounce/scheduling ticks might not get its
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own frame, only the surrounding samples).
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Usage:
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python tools/extract_dio_timeline.py captures/gateway_20260829_164540.csv \\
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--out captures/dio_20260829.csv
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"""
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import argparse
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import csv
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from pathlib import Path
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CAN_ID_STATUS = 0x100
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def bits(n: int, count: int) -> str:
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return "".join(str((n >> i) & 1) for i in range(count))
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def main() -> int:
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parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
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parser.add_argument("gateway_log")
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parser.add_argument("--out", required=True, help="Output CSV path (t, inputs, outputs)")
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args = parser.parse_args()
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samples = []
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with open(args.gateway_log, newline="") as f:
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for row in csv.DictReader(f):
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if int(row["arbitration_id"], 16) != CAN_ID_STATUS:
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continue
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data = bytes.fromhex(row["data_hex"])
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if len(data) < 2:
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continue
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samples.append((float(row["t"]), data[0], data[1]))
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with open(args.out, "w", newline="") as f:
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w = csv.writer(f)
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w.writerow(["t", "inputs", "outputs"])
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for t, ins, outs in samples:
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w.writerow([t, ins, outs])
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print(f"Wrote {len(samples)} status samples to {args.out}\n")
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print("Transitions (IN1-4 / OUT1-2, bit0 first):")
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prev = None
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for t, ins, outs in samples:
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cur = (ins, outs)
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if cur != prev:
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print(f" t={t:8.3f}s IN={bits(ins, 4)} OUT={bits(outs, 2)}")
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prev = cur
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return 0
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if __name__ == "__main__":
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raise SystemExit(main())
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