Initial commit, basic functionality (send gcode to printer, pause, resume, send intermediate command)

README

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+This is the beginning of a python-based host software for reprap printers.
+
+Currently contains printcore.py, which requires pyserial to be installed.
+
+Using printcore:
+
+p=printcore('/dev/ttyUSB0',115200)
+p.startprint(data) # data is an array of gcode lines
+p.send_now("M105") # sends M105 as soon as possible
+p.pause()
+p.resume()
+p.disconnect()
+

printcore.py

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+from serial import Serial
+from threading import Thread
+import time
+
+class printcore():
+    def __init__(self,port=None,baud=None):
+        self.baud=None
+        self.port=None
+        self.printer=None
+        self.clear=0
+        self.mainqueue=[]
+        self.priqueue=[]
+        if port is not None and baud is not None:
+            print port, baud
+            self.connect(port, baud)
+            print "connected\n"
+        self.readthread=None
+        self.queueindex=0
+        self.lineno=0
+        self.resendfrom=-1
+        self.online=False
+        self.printing=False
+        self.sentlines={}
+        
+    def disconnect(self):
+        if(self.printer):
+            self.printer.close()
+        self.printer=None
+        self.online=False
+        self.printing=False
+        
+    def connect(self,port=None,baud=None):
+        if(self.printer):
+            self.disconnect()
+        if port is not None:
+            self.port=port
+        if baud is not None:
+            self.baud=baud
+        if self.port is not None and self.baud is not None:
+            self.printer=Serial(self.port,self.baud,timeout=5)
+            Thread(target=self._listen).start()
+            
+    def _listen(self):
+        """This function acts on messages from the firmware
+        """
+        time.sleep(1)
+        print "listening:"
+        while(True):
+            if(not self.printer or not self.printer.isOpen):
+                print "port not open"
+                break
+            line=self.printer.readline()
+            print "RECV:",line
+            if(line.startswith('start')):
+                self.clear=True
+                self.online=True
+            elif(line.startswith('ok')):
+                self.clear=True
+                self.resendfrom=-1
+                #put temp handling here
+            elif(line.startswith('Error')):
+                pass
+            if "Resend" in line or "rs" in line:
+                toresend=int(line.split(':')[1])
+                self.resendfrom=toresend
+                self.clear=True
+        print "done listening"
+            
+    def checksum(self,command):
+        return reduce(lambda x,y:x^y, map(ord,command))
+        
+    def startprint(self,data):
+        if(self.printing):
+            return False
+        self.printing=True
+        self.mainqueue=[]+data
+        self._send("M110",-1, True)
+        Thread(target=self._print).start()
+        return True
+        
+    def pause(self):
+        self.printing=False
+        
+    def resume(self):
+        self.printing=True
+        threading.Thread(target=self._print).start()
+        
+    def send_now(self,command):
+        if(self.printing):
+            self.priqueue+=[command]
+        else:
+            self._send(command)
+        
+    def _print(self):
+        while(self.printing and self.printer):
+            self.sendnext()
+        
+    def sendnext(self):
+        if(not self.printer):
+            return
+        if(self.resendfrom>-1):
+            while(self.resendfrom<self.lineno):
+                while not self.clear:
+                    time.sleep(0.001)
+                self.clear=False
+                self._send(self.sentlines[self.resendfrom],self.resendfrom,False)
+                self.resendfrom+=1
+            self.resendfrom=-1
+        for i in self.priqueue[:]:
+            while not self.clear:
+                time.sleep(0.001)
+            self.clear=False
+            self._send(i)
+            del(self.preque[0])
+        if(self.printing and self.queueindex<len(self.mainqueue)):
+            tline=self.mainqueue[self.queueindex]
+            if(not tline.startswith(';') and len(tline)>0):
+                while not self.clear:
+                    time.sleep(0.001)
+                self.clear=False
+                self._send(tline,self.lineno,True)
+            self.lineno+=1
+            self.queueindex+=1
+        else:
+            self.printing=False
+            self.queueindex=0
+            self.lineno=0
+            self._send("M110",-1, True)
+            
+    def _send(self, command, lineno=0, calcchecksum=False):
+        if(calcchecksum):
+            prefix="N"+str(lineno)+" "+command
+            command=prefix+"*"+str(self.checksum(prefix))
+            self.sentlines[lineno]=command
+        if(self.printer):
+            print "sending: "+command+"\n"
+            self.printer.write(command+"\n")
+
+if __name__ == '__main__':
+    p=printcore('/dev/ttyUSB0',115200)
+    time.sleep(5)
+    testdata="""G28
+G1 X0 Y0
+G1 X10 Y10
+G1 X0 Y0
+;
+"""
+    p.startprint(testdata.split('\n'))
+    time.sleep(10)
+    p.disconnect()