Ryan Malloy
2aaa6e32a5
Library dir: lib/AutoWire/ -> lib/KLine/ Site title, docs, CLAUDE.md, platformio.ini all updated. All 4 firmware environments build clean.
93 lines
3.4 KiB
C++
93 lines
3.4 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/checksum error.
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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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// Send TesterPresent (service 0x3E) to keep the diagnostic session alive.
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void sendTesterPresent();
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// Reset initialized state (for re-init after session loss)
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void reset() { _initialized = false; }
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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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// Detach UART TX from GPIO pin (so we can bit-bang)
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void detachUartTx();
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// Re-attach UART TX to GPIO pin (after bit-bang init)
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void reattachUartTx();
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// Discard echo bytes from half-duplex bus, verify they match expected.
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// Returns true if all echo bytes matched, false on bus contention.
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bool clearEcho(const uint8_t* expected, 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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// Parse ISO 14230 frame structure. Returns index of first data byte
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// (service ID position), or -1 on parse error.
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// Sets *dataLen to the number of data bytes.
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int8_t parseFrameData(const uint8_t* buf, uint8_t bufLen, uint8_t* dataLen);
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// Remaining timeout helper — clamps to 0 if already expired
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static uint16_t remainingMs(unsigned long startMs, 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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unsigned long _lastRequestMs; // for P3 keepalive timing
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static constexpr uint16_t P3_KEEPALIVE_MS = 4000; // send TesterPresent before P3max
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};
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