LucianoDev
4891eb6812
- Replace P1-P6 rational transfer function with factor/offset model for bench params - Add explicit rx/tx direction flags in bench XML configuration - Add T.Tank (BenchTemp) and P2 (AnalogSensor2) to temperature/pressure display - Apply SensorConfiguration calibration to pressure channels, fix empty sensors.xml fallback - Add live value labels to flowmeter charts - Hide pump live values and PSG encoder standalone label - Add K-Line connection state model, improve KWP service and status displays - Restructure .claude/skills into subdirectory format Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
75 lines
1.7 KiB
Markdown
75 lines
1.7 KiB
Markdown
# VP44 Protocol Reference
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Quick reference for hardware protocol constants used in HC_APTBS. Consult this before modifying any protocol-related code.
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---
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## DFI encoding (EEPROM address 0x0044 on VP44 ECU)
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**Read (raw byte → DFI value):**
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```csharp
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dfi = (sbyte)raw * 3.0 / 256.0
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```
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**Write (DFI value → raw byte):**
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```csharp
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raw = (sbyte)((dfi * 256.0f) / 3.0f)
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// If raw == 0, use 1 — the ECU rejects zero
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```
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**Checksum:**
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```csharp
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checksum = (byte)(0 - (byte)rawValue)
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```
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---
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## IIR low-pass filter (PcanAdapter.PassFilterUpdate)
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```csharp
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result = Math.Round(prev + alpha * (value - prev), 4)
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```
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Used to smooth CAN bus sensor readings. The `alpha` coefficient controls responsiveness vs. noise rejection.
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---
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## OEM legitimation (PcanAdapter.Connect)
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```csharp
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token = (20120378UL << 32) | 21200UL
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```
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Sent as a CAN frame to authenticate with the bench controller. Without this, the bench ignores all commands.
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---
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## K-Line / KWP timing
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**Inter-byte delay** (`KW1281Connection.SendPacket`):
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```csharp
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Thread.Sleep(5) // after each byte — KWP protocol requirement, NOT a workaround
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```
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**5-baud slow-init** (`KwpCommon.WakeUp`):
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- Bit-bangs the ECU address at 5 baud on the K-Line
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- Sleep durations in WakeUp are protocol-mandated — do not change
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**Session lifetime**:
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- One `FtdiInterface` open/close per KWP operation
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- ECU expects a fresh session per dialog — do not pool connections
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---
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## CAN bus (PCAN-Basic, 500 kbps)
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- Channel: `PCAN_USBBUS1`
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- Baud: `PCAN_BAUD_500K`
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- Read thread polls with `Thread.Sleep(2)` in `DrainMessageQueue` (known debt)
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---
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## Caution
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Do not change any of these values without understanding the hardware protocol specification. Incorrect values can cause ECU communication failures or bench malfunction.
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