package sim // import "github.com/anviod/EtherCAT/internal/sim" Package sim provides L2 EtherCAT slave and bus simulation for testing. 包 sim 提供用于测试的 L2 EtherCAT 从站和总线模拟。 This package implements a software EtherCAT slave with 64KB backing memory, register shadowing, EEPROM simulation, and frame processing capability. It is designed for unit testing and protocol validation without real hardware. 本包实现了带 64KB 后备内存、寄存器影子、EEPROM 模拟和帧处理能力的 软件 EtherCAT 从站，用于在没有真实硬件的情况下进行单元测试和协议验证。 # Key types - L2Slave: software EtherCAT slave with register mapping - L2Bus: bus with multiple slaves, implements ecmd.Framer - L2EEPROM: EEPROM simulation for testing # Usage bus := &sim.L2Bus{} bus.Slaves = append(bus.Slaves, sim.NewL2Slave()) frame, _ := bus.New(64) // ... fill datagrams ... iframes, err := bus.Cycle() TYPES type ALControl struct { // Has unexported fields. } ALControl represents the AL Control register (0x0120-0x0121). Each field maps to a specific bit in the register: Byte 0: [idSel(7) | devIDReq(6) | errorInd(5) | ack(4) | state(3:0)] Byte 1: [wdDiv2(7:5) | wdDiv(4:3) | wdTOut(2) | frcErr(1) | wdTrigger(0)] func (c *ALControl) Latch(shadow []byte, shadowWriteMask []bool) Latch applies shadow register writes to the AL Control register. State changes are gated: if the device is in error, state transitions that don't clear the error are blocked. func (c *ALControl) Read(offs uint16, dp *uint8) bool Read reads a byte from the AL Control register at the given offset. Offset 0 returns the state and control bits; offset 1 returns watchdog and divider configuration. func (c *ALControl) WriteInteract(offs uint16) bool WriteInteract returns whether the AL Control register is writable from the EtherCAT side. type ALStatus struct { // Has unexported fields. } ALStatus represents the AL Status register (0x0130-0x0135). Each field maps to a specific bit in the register: Byte 0: state (3:0) Byte 1: [reserved(7:2) | errInd(1) | stateChangeAck(0)] Byte 2-3: devID (16-bit) Byte 4: wdState (bit 0) Byte 5: reserved func (s *ALStatus) Latch(shadow []byte, shadowWriteMask []bool) Latch is a no-op: the AL Status register is read-only. func (s *ALStatus) Read(offs uint16, dp *uint8) bool Read reads a byte from the AL Status register at the given offset. func (s *ALStatus) WriteInteract(offs uint16) bool WriteInteract returns false: the AL Status register is read-only from the EtherCAT side. type ALStatusControl struct { // Has unexported fields. } ALStatusControl holds shared state between the AL Control and AL Status registers. It tracks the error condition and provides access to both register views. func NewALStatusControl() *ALStatusControl NewALStatusControl creates a new ALStatusControl with initialized control and status register views. func (sc *ALStatusControl) ControlReg() *ALControl ControlReg returns the AL Control register view. func (sc *ALStatusControl) InError() bool InError returns true if the device is in an error state. func (sc *ALStatusControl) IsECATWritable() bool IsECATWritable returns true, indicating the EtherCAT side can write to the AL Control register. func (sc *ALStatusControl) SetError(seterr bool) SetError sets or clears the error state. func (sc *ALStatusControl) StatusReg() *ALStatus StatusReg returns the AL Status register view. type DevMapping struct { StartAddr uint16 LengthField uint16 DeviceField MMDevice } DevMapping implements the MMapping interface, describing a contiguous region of register space that is mapped to a specific MMDevice. func (d DevMapping) Device() MMDevice Device returns the MMDevice that handles this mapped region. func (d DevMapping) Length() uint16 Length returns the length of the mapping in bytes. func (d DevMapping) Start() uint16 Start returns the starting address of the mapping. type FrameProcessor interface { ProcessFrame(*ecfr.Frame) *ecfr.Frame } FrameProcessor processes an EtherCAT frame, potentially modifying datagram data and working counters. It returns the processed frame. type Framer interface { New(maxdatalen int) (*ecfr.Frame, error) Cycle() ([]*ecfr.Frame, error) Close() error } Framer is the local interface for frame-based EtherCAT communication. It is defined here to avoid a circular dependency on the ecmd package. L2Bus satisfies ecmd.Framer through structural typing. type L2Bus struct { Slaves []FrameProcessor // Has unexported fields. } L2Bus represents a layer-2 EtherCAT bus with a collection of slaves. Frames are created through New(), processed through all slaves during Cycle(), and the bus is cleaned up with Close(). func (b *L2Bus) Close() error Close closes the bus and releases any resources. Currently a no-op. func (b *L2Bus) Cycle() (iframes []*ecfr.Frame, err error) Cycle processes all queued frames through the slave chain: commit → copy → overlay → process. 处理所有排队帧通过从站链：提交 → 复制 → 解析 → 处理。 Outgoing frame queue is cleared after Cycle returns. func (b *L2Bus) New(maxdatalen int) (fr *ecfr.Frame, err error) New creates a new EtherCAT frame with the specified max datagram data length. 创建指定最大数据长度的 EtherCAT 帧。 type L2EEPROM struct { Array [8 * 1024]uint16 Addr uint32 DataScratch [8]byte // data in wire encoding PDIControl bool WriteEnable bool ChecksumError bool EENotLoaded bool MissingAcknowledge bool ErrorWriteEnable bool Busy bool } L2EEPROM simulates an EtherCAT EEPROM with 8192 16-bit words. It provides register-level access through the L2EEPROMRegisterSet. func NewL2EEPROM() *L2EEPROM NewL2EEPROM creates a new L2EEPROM instance with pre-filled test data. Each word is initialized to 0xEE00 + index. func (ee *L2EEPROM) Reg() *L2EEPROMRegisterSet Reg returns the register set interface for accessing EEPROM registers in the 0x0500-0x050F address range. type L2EEPROMRegisterSet struct { *L2EEPROM } L2EEPROMRegisterSet implements MMDevice for the EEPROM register area (addresses 0x0500-0x050F). func (ee *L2EEPROMRegisterSet) Latch(shadow []byte, shadowWriteMask []bool) Latch applies shadow register writes to the EEPROM state. FIXED: The address bytes (offsets 4-7) are now properly reconstructed using correct uint32 type conversions. The original code had a bug where uint32(shadow[7]) << 32 would overflow to 0 on a 32-bit type. The fix uses uint32(shadow[7]) | uint32(shadow[6])<<8 | uint32(shadow[5])<<16 | uint32(shadow[4])<<24 to construct the full 32-bit address with proper type promotion before each shift. func (ee *L2EEPROMRegisterSet) Read(offs uint16, dp *uint8) bool Read reads a byte from the EEPROM register area at the given offset. The register layout is: 0x00: PDI Control (bit 0 = PDI access) 0x01: PDI Access State (reserved) 0x02: EEPROM Control/Status (bit 0 = write enable, bits 6-7 = address/size config) 0x03: EEPROM Command/Status (bits 0-1 = command, bits 3-7 = status flags) 0x04-0x07: EEPROM Address (32-bit, little-endian) 0x08-0x0F: EEPROM Data (64-bit scratch buffer) func (ee *L2EEPROMRegisterSet) WriteInteract(offs uint16) bool WriteInteract handles write interaction for the EEPROM register area. Register 0x02 (Control) and 0x03 (Command) are writeable only when not busy. type L2Slave struct { BackingMemory [1 << 16]byte ALStatusControl *ALStatusControl EEPROM *L2EEPROM // Has unexported fields. } L2Slave represents a layer-2 EtherCAT slave device with 64KB of backing memory, register shadowing, and frame processing capability. func NewL2Slave() *L2Slave NewL2Slave creates a new L2Slave with initialized ET1100 signature, AL Status/Control registers, and EEPROM. func (s *L2Slave) ProcessFrame(infr *ecfr.Frame) (ofr *ecfr.Frame) ProcessFrame processes an EtherCAT frame through this slave. 通过本从站处理 EtherCAT 帧。 For each datagram: if physically addressed, reads/writes backing memory, updates WKC. Register shadow is latched after all datagrams. 对每个数据报：若物理寻址匹配，读写后备内存并更新 WKC。处理完成后锁存寄存器影子。 Perf: non-register addresses (>= 0x1000) use bulk copy() — 100x fewer calls. 性能优化：非寄存器地址使用批量 copy()，减少 100 倍函数调用。 type MMDevice interface { Read(offs uint16, dp *uint8) bool WriteInteract(offs uint16) bool Latch(shadow []byte, shadowWriteMask []bool) } MMDevice represents a memory-mapped device that can be read from, written to, and latched with shadow register values. type MMapping interface { Start() uint16 Length() uint16 Device() MMDevice } MMapping represents a mapping of a memory region to a device.