new: implemented can.obd2 builtin parser

modules/can/can_obd2_message.go

@@ -0,0 +1,72 @@
+package can
+
+import (
+	"fmt"
+)
+
+// https://en.wikipedia.org/wiki/OBD-II_PIDs
+
+// https://www.csselectronics.com/pages/obd2-explained-simple-intro
+// https://www.csselectronics.com/pages/obd2-pid-table-on-board-diagnostics-j1979
+
+// https://stackoverflow.com/questions/40826932/how-can-i-get-mode-pids-from-raw-obd2-identifier-11-or-29-bit
+
+// https://github.com/ejvaughan/obdii/blob/master/src/OBDII.c
+
+// TODO: add support for 29bit identifiers
+const OBD2BroadcastRequestID = 0x7DF
+const OBD2ECUResponseMinID = 0x7E0
+const OBD2ECUResponseMaxID = 0x7EF
+
+type OBD2Service uint8
+
+func (s OBD2Service) String() string {
+	switch s {
+	case 0x01:
+		return "Show current data"
+	case 0x02:
+		return "Show freeze frame data"
+	case 0x03:
+		return "Show stored Diagnostic Trouble Codes"
+	case 0x04:
+		return "Clear Diagnostic Trouble Codes and stored values"
+	case 0x05:
+		return "Test results, oxygen sensor monitoring (non CAN only)"
+	case 0x06:
+		return "Test results, other component/system monitoring (Test results, oxygen sensor monitoring for CAN only)"
+	case 0x07:
+		return "Show pending Diagnostic Trouble Codes (detected during current or last driving cycle)"
+	case 0x08:
+		return "Control operation of on-board component/system"
+	case 0x09:
+		return "Request vehicle information"
+	case 0x0A:
+		return "Permanent Diagnostic Trouble Codes (DTCs) (Cleared DTCs)"
+	}
+
+	return fmt.Sprintf("service 0x%x", uint8(s))
+}
+
+type OBD2MessageType uint8
+
+const (
+	OBD2MessageTypeRequest OBD2MessageType = iota
+	OBD2MessageTypeResponse
+)
+
+func (t OBD2MessageType) String() string {
+	if t == OBD2MessageTypeRequest {
+		return "request"
+	} else {
+		return "response"
+	}
+}
+
+type OBD2Message struct {
+	Type    OBD2MessageType
+	ECU     uint8
+	Service OBD2Service
+	PID     OBD2PID
+	Size    uint8
+	Data    []uint8
+}