Ryan Malloy
8ba53630c0
New protocol handler alongside BMW I/K-Bus: - KLineObd2: 5-baud slow init, fast init (TiniPulse), request/response with half-duplex echo clearing, PID convenience wrapper - Obd2Pids.h: ~20 common PIDs with SAE J1979 decode helpers - obd2_scanner.cpp: polls RPM, speed, coolant, throttle, voltage Build config changes: - config.h: KLINE_* defaults (10400/8N1/MOD256/no idle detect) - platformio.ini: build_src_filter separates sketches, new [env:obd2-scanner] environment with KLINE_TX_INVERT=0
69 lines
2.3 KiB
C++
69 lines
2.3 KiB
C++
#pragma once
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// OBD-II K-line protocol handler (ISO 9141 / ISO 14230)
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// Uses KLineTransport for UART, ring buffers, and bus management.
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// Handles 5-baud slow init, fast init, request/response framing,
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// and half-duplex echo clearing.
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#include <Arduino.h>
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#include "KLineTransport.h"
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#include "driver/uart.h"
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#ifndef KLINE_RESPONSE_TIMEOUT_MS
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#define KLINE_RESPONSE_TIMEOUT_MS 2000
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#endif
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#ifndef KLINE_ECHO_TIMEOUT_MS
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#define KLINE_ECHO_TIMEOUT_MS 100
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#endif
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class KLineObd2 {
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public:
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KLineObd2(KLineTransport& transport);
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// ISO 9141 5-baud slow init — bit-bangs target address at 5 baud,
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// then reads sync (0x55) and keyword bytes from ECU.
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// Returns true if ECU responds with valid sync + keywords.
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bool slowInit(uint8_t targetAddr = 0x33);
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// ISO 14230 fast init — 25ms LOW + 25ms HIGH TiniPulse,
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// then reads StartComm response.
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bool fastInit();
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// Send an OBD-II request. Frames the message and discards echo bytes.
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// data[] should contain: [header, source, target, mode, pid, ...]
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// For simple PID requests, use requestPid() instead.
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void sendRequest(const uint8_t* data, uint8_t len);
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// Read response from ECU. Blocks until response received or timeout.
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// Returns number of bytes read, or 0 on timeout.
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uint8_t readResponse(uint8_t* buf, uint8_t maxLen,
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uint16_t timeoutMs = KLINE_RESPONSE_TIMEOUT_MS);
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// Convenience: send a mode/PID request and read the response.
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// Returns response data length (excluding header/checksum), or 0 on failure.
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uint8_t requestPid(uint8_t mode, uint8_t pid,
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uint8_t* response, uint8_t maxLen);
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bool isInitialized() const { return _initialized; }
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// Protocol info from init handshake
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uint8_t keyword1() const { return _kw1; }
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uint8_t keyword2() const { return _kw2; }
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private:
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// Bit-bang a single byte at 5 baud (200ms per bit) on TX pin
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void sendByte5Baud(uint8_t data);
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// Discard echo bytes from half-duplex bus
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void clearEcho(uint8_t count);
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// Read a single byte with timeout
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int readByteTimeout(uint16_t timeoutMs);
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KLineTransport& _transport;
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bool _initialized;
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uint8_t _kw1;
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uint8_t _kw2;
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uint8_t _testerAddr; // our address (0xF1 = external test equipment)
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uint8_t _ecuAddr; // ECU address from init response
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};
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