| View previous topic :: View next topic | 
	
	
		| Author | Message | 
	
		| pvol 
 
 
 Joined: 10 Oct 2008
 Posts: 46
 Location: GREECE
 
 
			    
 
 | 
			
				| change pins TX/RX |  
				|  Posted: Sat Dec 20, 2008 3:04 am |   |  
				| 
 |  
				| Hello everybody 
 I wonder if I could change pins of tx/rx on 18f4620.
 For example:
 
  	  | Code: |  	  | #use RS232(baud=9600, xmit=PIN_C6, rcv=PIN_C7) | 
 change to
 
  	  | Code: |  	  | #use RS232(baud=9600, xmit=PIN_A0, rcv=PIN_A1) | 
 Is it possible to do this?
 Will it work?
 |  | 
	
		|  | 
	
		| vijay s 
 
 
 Joined: 20 Oct 2007
 Posts: 17
 Location: coimbatore,india
 
 
			        
 
 | 
			
				|  |  
				|  Posted: Sat Dec 20, 2008 4:36 am |   |  
				| 
 |  
				| To make this PIN work as UART you have to use FORCE_SW in #use rs232. it will generate software UART routines for the specified Pin.
 _________________
 with regards
 vijay s
 |  | 
	
		|  | 
	
		| dyeatman 
 
 
 Joined: 06 Sep 2003
 Posts: 1968
 Location: Norman, OK
 
 
			    
 
 | 
			
				|  |  
				|  Posted: Sat Dec 20, 2008 7:56 am |   |  
				| 
 |  
				| The hardware UART cannot be moved from C6/C7.  If you change either one of those pins (or even if you swap TX and RX) in the USE RS232 command line, the compiler will automatically generate a software UART and the hardware UART will be disabled.   It should not be necessary to use the FORCE_SW switch in the command line. 
 One word of caution. Using a sofware UART could be a problem if you are usings any non-UART interrupts.    An interrupt from an ADC, for example, can interfere with a software UART and affect transmission or reception.
 
 Last edited by dyeatman on Sat Dec 20, 2008 2:40 pm; edited 1 time in total
 |  | 
	
		|  | 
	
		| asmboy 
 
 
 Joined: 20 Nov 2007
 Posts: 2128
 Location: albany ny
 
 
			      
 
 | 
			
				| perhaps a razor knife and rework wire is the answer |  
				|  Posted: Sat Dec 20, 2008 9:41 am |   |  
				| 
 |  
				| if this question was generated because of a PCB layout error the real solution is a razor knife - and some Kynar or fine teflon rework wiring to get the correct wiring  to the hardware UART - the hardware uart is your friend in all circumstances - the software uart is strictly for  the desperate.
  |  | 
	
		|  | 
	
		|  |