HELP!!! nothing going through my USART!!!

[Guyver]

WHats wrong with this code? I cant seem to get anything to come out from the transmitter pin

Please can u help

	LIST P = 16F628		;	MICROCONTROLLER USED
	#include "P16F628.inc"	;	HEADER FILE (CONTAINS APPROPRIATE EQUATES SECTION


;===========================================================================
;		CONFIGURATION WORD				
;===========================================================================

	ERRORLEVEL 0,	-302	;	STOPS BANK SELECTION MESSAGES
	__CONFIG	0x3D18		;CONFIGURATION WORD (SETS OSCILATOR ETC)

	org	0x0000

	bsf 	STATUS, RP0			;select bank 1

	MOVLW 0X07
	MOVWF CMCON

	MOVLW B'00100011'
	MOVWF TRISA

	MOVLW B'00000010'
	MOVWF TRISB

	MOVLW D'12'
	MOVWF SPBRG

	MOVLW B'00100100'
	MOVWF TXSTA

	MOVLW B'00000000'
	MOVWF PIE1
	
	MOVLW	b'00100100'
	MOVWF	TXSTA				;configure USART transmission

	clrf	PIE1
	
	bcf		STATUS,	RP0			;return to bank 0
	
	bsf		RCSTA, SPEN

;----------------------------------------------------------------------------
;						Main program
;----------------------------------------------------------------------------

START
	BANKSEL PORTA
	BTFSC PORTA, 0		;Check to see if the carry is set
	CALL CAMERA_A
	BTFSC PORTA, 1
	CALL CAMERA_B
	GOTO START		;Loop forever

CAMERA_A
C_A    
	BANKSEL TXSTA
    BTFSS TXSTA, TRMT
    GOTO C_A
    BANKSEL TXREG
    MOVLW H'41'
    MOVWF TXREG
	RETURN


CAMERA_B
C_B
    BANKSEL TXSTA
    BTFSS TXSTA, TRMT
    GOTO C_B
    BANKSEL TXREG
    MOVLW H'42'
    MOVWF TXREG
	RETURN

	END

 

[Matt(Pic progger)]

:idea:
change......

;===========================================================================
; CONFIGURATION WORD
;===========================================================================

ERRORLEVEL 0, -302 ; STOPS BANK SELECTION MESSAGES
__CONFIG 0x3D18 ;CONFIGURATION WORD (SETS OSCILATOR ETC)

org 0x0000

bsf STATUS, RP0 ;select bank 1

MOVLW 0X07
MOVWF CMCON

etc........


to........


;===========================================================================
; CONFIGURATION WORD
;===========================================================================

ERRORLEVEL 0, -302 ; STOPS BANK SELECTION MESSAGES
__CONFIG 0x3D18 ;CONFIGURATION WORD (SETS OSCILATOR ETC)

org 0x0000

MOVLW 0X07
MOVWF CMCON

bsf STATUS, RP0 ;select bank 1

etc......


You are not disabling the comparators, as you are trying to do this in page 1 (cmcon is in page 0), this data will be loaded into VRCON in your original code.

hope this helps

 

[Guyver]

YEA it works now, thnaks m8.

Just another qucik question while yer here, how u put a delay into the code for 2seconds and call it into camera a and camera b? Cos its checing it a couple of thausands of time every seconds

 

[Matt(Pic progger)]

:idea:

START
BANKSEL PORTA
BTFSC PORTA, 0 ;Check to see if the carry is set
CALL CAMERA_A
BTFSC PORTA, 1
CALL CAMERA_B
GOTO START ;Loop forever

CAMERA_A
C_A
BANKSEL TXSTA
BTFSS TXSTA, TRMT
GOTO C_A
BANKSEL TXREG
MOVLW H'41'
MOVWF TXREG

LOOP_CAMA
BTFSC PORTA, 0 ;HAS CAMERA A INPUT GONE LOW?
GOTO LOOP_CAMA ;NO, LOOP UNTIL LOW

RETURN


This will keep the prog "trapped" after transmiting "CAMA" and only return when the line (input) has gone low again..... do the same for CAMB

btw, it may not be a bad idea to comment your code abit more, this is not a go, just some advise, it helps others to help you (and to help yourself a few months later!)

Hope this helps!

 

[Guyver]

ive done it

CAMERA_B
C_B
BANKSEL TXSTA
btfss TXSTA, TRMT
goto C_B
BANKSEL TXREG
movlw H'42'
movwf TXREG
return

LOOP_CAMB
BTFSC PORTB, 0 ;HAS CAMERA B INPUT GONE LOW?
GOTO LOOP_CAMB ;NO, LOOP UNTIL LOW
RETURN

does that not need a calling funtion? or does it do the loop straight after that bit of code??

sorry, i forgot about the comments, just wanted to get the thing working first

 

[Guyver]

WHOOPs,

the code is meant to be like this, i forgot about changing the names

CAMERA_B
C_B
    BANKSEL TXSTA
    btfss TXSTA, TRMT
    goto C_B
    BANKSEL TXREG
    movlw H'42'
    movwf TXREG

LOOP_C_B  
	BTFSC PORTB, 0 				;HAS CAMERA B INPUT GONE LOW? 
	GOTO LOOP_C_B 				;NO, LOOP UNTIL LOW 
	RETURN

 

[Matt(Pic progger)]

:?:

Seems fine, have you swapped the input for camera B to port B,0 then?

btw, a usefull way to keep track of what's on what ports is to assign equates, sorry if I am patronising you..... here's an example....


;PORTA ASSIGNMENTS
CAM_A EQU H'00' ;CAMERA A INPUT 1=ACTIVE

;PORTB ASSIGNMENTS
CAM_B EQU H'00' ;CAMERA B INPUT 1=ACTIVE

Now when checking for your camera you can write.....

BTFSS PORTB,CAM_B ;IS CAMERA B ACTIVE?

Looking at your comments in the previous equates anyone can see that CAM_B is set to PORTB,0 and that a logic 1 is active. It makes it much easier to read.

There is another HUGE advantage to using equates....... lets say you have 20 instances of BTFSS PORTB,CAM_B......... You now want to change CAM_B input to PORTB,1....... In your old code you have to change all 20 instances of PORTB,0 to PORTB,1...... But with equates you simply.......

;PORTB ASSIGNMENTS
CAM_B EQU H'01' ;CAMERA B INPUT 1=ACTIVE

Recompile, and it's all done........

There are other features within MPLAB that allow you to use Macro's I avoid using these as I find they make the code difficult to read.....Each to their own!!

Hope this helps!

 

[Exo]

Or, even simpler

#Define CameraB PORTB,0

and in your code you can write

BTFSS CameraB

 

[Matt(Pic progger)]

:lol:

You are correct, however, like I said, i personally, and it is just a personal thing, don't like using defines....... I have had to work with other peoples code that looks a bit like this (ok a BIT exagerated :wink: )

CAMERA_ON
CAMERA_OFF
RESET_TIMER
CHECK_INTS

You get the idea..... what do these mean??? you have to keep checking the defines, anyway, I suppose, in moderation (like none! :wink: ), they can be usefull (he admitted with "tounge-in-cheek")

I am probably just too old to keep track of more than 1 thi........ what was I saying?? :wink: