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6 changes: 5 additions & 1 deletion framertu.go
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,6 @@ func NewRTUFrame(packet []byte) (*RTUFrame, error) {
Function: uint8(packet[1]),
Data: packet[2 : pLen-2],
}

return frame, nil
}

Expand Down Expand Up @@ -62,6 +61,11 @@ func (frame *RTUFrame) Bytes() []byte {
return bytes
}

// GetFunction returns the Modbus function code.
func (frame *RTUFrame) GetAddress() uint8 {
return frame.Address
}

// GetFunction returns the Modbus function code.
func (frame *RTUFrame) GetFunction() uint8 {
return frame.Function
Expand Down
16 changes: 10 additions & 6 deletions servertu.go
Original file line number Diff line number Diff line change
Expand Up @@ -9,17 +9,17 @@ import (

// ListenRTU starts the Modbus server listening to a serial device.
// For example: err := s.ListenRTU(&serial.Config{Address: "/dev/ttyUSB0"})
func (s *Server) ListenRTU(serialConfig *serial.Config) (err error) {
func (s *Server) ListenRTU(serialConfig *serial.Config, deviceId uint8) (err error) {
port, err := serial.Open(serialConfig)
if err != nil {
log.Fatalf("failed to open %s: %v\n", serialConfig.Address, err)
}
s.ports = append(s.ports, port)
go s.acceptSerialRequests(port)
go s.acceptSerialRequests(port, deviceId)
return err
}

func (s *Server) acceptSerialRequests(port serial.Port) {
func (s *Server) acceptSerialRequests(port serial.Port, deviceId uint8) {
for {
buffer := make([]byte, 512)

Expand All @@ -41,10 +41,14 @@ func (s *Server) acceptSerialRequests(port serial.Port) {
log.Printf("bad serial frame error %v\n", err)
return
}
if frame.GetAddress() == deviceId {
request := &Request{port, frame}
s.requestChan <- request
} else {
log.Printf("wrong slave address")
}

request := &Request{port, frame}

s.requestChan <- request

}
}
}