113 lines
2.5 KiB
C++
113 lines
2.5 KiB
C++
/**
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* @file can_msg_tx.h
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*
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* CAN message transmission
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*
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* @date Mar 13, 2020
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* @author Matthew Kennedy, (c) 2012-2020
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*/
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#pragma once
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#include <cstdint>
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#include <cstddef>
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#include "os_access.h"
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/**
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* Represent a message to be transmitted over CAN.
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*
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* Usage:
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* * Create an instance of CanTxMessage
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* * Set any data you'd like to transmit either using the subscript operator to directly access bytes, or any of the helper functions.
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* * Upon destruction, the message is transmitted.
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*/
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class CanTxMessage
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{
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public:
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/**
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* Create a new CAN message, with the specified extended ID.
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*/
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explicit CanTxMessage(uint32_t eid, uint8_t dlc = 8, bool isExtended = false);
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/**
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* Destruction of an instance of CanTxMessage will transmit the message over the wire.
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*/
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~CanTxMessage();
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#if EFI_CAN_SUPPORT
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/**
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* Configures the device for all messages to transmit from.
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*/
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static void setDevice(CANDriver* device);
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#endif // EFI_CAN_SUPPORT
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/**
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* @brief Read & write the raw underlying 8-byte buffer.
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*/
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uint8_t& operator[](size_t);
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/**
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* @brief Write a 16-bit short value to the buffer. Note: this writes in big endian byte order.
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*/
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void setShortValue(uint16_t value, size_t offset);
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/**
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* @brief Set a single bit in the transmit buffer. Useful for single-bit flags.
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*/
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void setBit(size_t byteIdx, size_t bitIdx);
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void setDlc(uint8_t dlc);
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protected:
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#if EFI_CAN_SUPPORT
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CANTxFrame m_frame;
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#else // not EFI_CAN_SUPPORT
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uint8_t m_data8[8];
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#endif // EFI_CAN_SUPPORT
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private:
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#if EFI_CAN_SUPPORT
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static CANDriver* s_device;
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#endif // EFI_CAN_SUPPORT
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};
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/**
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* A CAN message based on a type, removing the need for manually flipping bits/bytes.
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*/
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template <typename TData>
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class CanTxTyped final : public CanTxMessage
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{
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#if EFI_CAN_SUPPORT
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static_assert(sizeof(TData) <= sizeof(CANTxFrame::data8));
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#endif // EFI_CAN_SUPPORT
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public:
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explicit CanTxTyped(uint32_t eid) : CanTxMessage(eid, sizeof(TData)) { }
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#if EFI_CAN_SUPPORT
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/**
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* Access members of the templated type.
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*
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* So you can do:
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* CanTxTyped<MyType> d;
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* d->memberOfMyType = 23;
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*/
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TData* operator->() {
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return reinterpret_cast<TData*>(&m_frame.data8);
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}
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TData& get() {
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return *reinterpret_cast<TData*>(&m_frame.data8);
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}
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#endif // EFI_CAN_SUPPORT
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};
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template <typename TData>
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void transmitStruct(uint32_t eid)
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{
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CanTxTyped<TData> frame(eid);
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// Destruction of an instance of CanTxMessage will transmit the message over the wire.
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// see CanTxMessage::~CanTxMessage()
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populateFrame(frame.get());
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}
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