help needed for 7 segment display

[mainman]

I'm looking to code a 16f84 PIC chip that makes a seven segment display output H E L P. I've looked all over the internet with no luck. I was wondering if anyone knew any code that would help?


many thanks

 

[Nigel Goodwin]

You just need to switch four different patterns to the display, you're unlikely to find EXACTLY what you want, because it's such a strange request - but it's trivial to do.

 

[mabauti]

I think this can be useful to you :
https://www.mikroe.com/en/books/picbook/7_08chapter.htm

 

[ericgibbs]

hi,
If you use the good example that 'mabauti' has posted, you will have to extend the Bcdto7Seg table and pointers, to cover 'HELP'

 

[Gayan Soyza]

Here is the body of the code I wrote for you.The initialize part and the delay you can do.In this example PORTA connecting to common cathodes & segment pins connects to PORTB.
Note that With this simple method you can only show letters.

;NOTES***********************************************************

;COMMON CATHODE SEGMENTS DISPLAY "HELP"

;COMMON CATHODES SHOULD CONNECT TO PORTA ACORDING TO THIS TABLE

;SEGMENTS STARTING FROM LEFT TO RIGHT

;SEG4	SEG3	SEG2	SEG1
;H	E	L	P
;RA0	RA1	RA2	RA3


;SEGMENT PINS SHOULD CONNECT TO PORTB ACORDING TO THIS TABLE
;SAME PINS LINKS TO OTHER SEGMENT PINS

;SEGMENT A-RB0
;SEGMENT B-RB1
;SEGMENT C-RB2
;SEGMENT D-RB3
;SEGMENT E-RB4
;SEGMENT F-RB5
;SEGMENT G-RB6

;DELAY SHOULD BE ABOUT 10MS

;****************************************************************

HELLO	 MOVLW B'00001'		;TURN ON RA0 & OFF OTHERS
	 MOVWF PORTA
	 MOVLW B'1110011'	;DISPLAY LETTER P
	 MOVWF PORTB
	 CALL  DELAY 
	
	 MOVLW B'00010'		;TURN ON RA1 & OFF OTHERS
	 MOVWF PORTA
	 MOVLW B'0111000'	;DISPLAY LETTER L
	 MOVWF PORTB
	 CALL  DELAY 

	 MOVLW B'00100'		;TURN ON RA2 & OFF OTHERS
	 MOVWF PORTA
	 MOVLW B'1111001'	;DISPLAY LETTER E
	 MOVWF PORTB
	 CALL  DELAY 

	 MOVLW B'01000'		;TURN ON RA3 & OFF OTHERS
	 MOVWF PORTA
	 MOVLW B'1110110'	;DISPLAY LETTER H
	 MOVWF PORTB
	 CALL  DELAY
	 GOTO  HELLO

 

[Mike - K8LH]

Gayan has provided a simple, elegant, intuitive example which should be more than enough to get the OP started.

 

[gramo]

Device 16F877

Xtal = 4

Dim Number As Byte
	
Initialization:

	TRISB = %00000000               ' Make PORTB all outputs

	Number = 0                      '
		
Main:
	 
	 Number = 0

	 Repeat                                    ' Create a loop
		  
		 Inc Number                        ' Increment the Number register
		 
		 GoSub Encode_Segment_Display      ' Convert to segment data and display it
		 
		 DelaymS 500                       ' Small delay to slow down counting
		  
	 Until Number = 4                         ' Loop until number = 4, then reset

	 Goto Main                                 ' Loop forever
	 
Encode_Segment_Display:

	SELECT Number
	    CASE 1			
	   		 PORTB = %01110110
	    CASE 2			
			 PORTB = %01111001
	    CASE 3			
	   		 PORTB = %00111000
	    CASE 4			
	   		 PORTB = %01110011
	ENDSELECT
	
	Return

Click here to watch this program/circuit in action
**broken link removed**


Hope that helps (The circuit shows a "1" - its just a saved piccy on my site, watch the video to see "H E L P" displayed on the segment)