Binary input Hex dispaly (7 segment LED)? - Page 8 - Electronic Circuits Projects Diagrams Free

dalmation · 28th November 2007, 03:26 AM

thanks- I will.

Not WORST case, though- the problem with the eeproms powering down to sleep mode doesnt happen with 7999/1 delays (which was the initial problem). I just need to figure out exatly what it is about this new setup that has allowed it to work- then I can hopefully keep that aspect the same, but fix the display.

Its 2am here- I'll get some sleep and continue tomorrow.

-Thanks again.

-Dal.

Mike, K8LH · 28th November 2007, 01:10 PM

Quote:

Originally Posted by Pommie

I think Mikes delay macro cannot handle very low values like 1 and consequently the delay time is very long.

The parameter range for the DelayUS() routine is 16..262159 (it's in the program listing). A parameter of '1' is out of range...

Seems you need to experiment with timing values while trying to figure out just how long and how often you need to drive those bus pins... Mike's (Pommie's) code looks fine though I would do it a little differently.

Code:

;
;  setup ports and display sub-system variables
;
        bsf     STATUS,RP0      ; bank 1                          |B1
        movlw   h'FF'           ;                                 |B1
        movwf   TRISA           ; make Port A all inputs          |B1
        clrf    TRISB           ; make Port B all outputs         |B1
        bcf     STATUS,RP0      ; bank 0                          |B0
        clrf    DigSel          ; init b7 digit select bit        |B0
        movlw   TRISA           ; address TRISA (in bank 1)       |B0
        movwf   FSR             ; setup for indirect access       |B0
;
;  display loop (8 msecs, 50% duty cycle, 62.5 Hz refresh rate)
;
Display
        swapf   PORTA,W         ; W = hi nybble in b3..b0 bits    |B0
        btfss   DigSel,7        ; left digit? yes, skip, else     |B0
        movf    PORTA,W         ; W = lo nybble in b3..b0 bits    |B0
        andlw   b'00001111'     ; mask off upper 4 bits           |B0
        call    SegData         ; get segment data in W           |B0
        iorwf   DigSel,W        ; add digit select bit in b7      |B0
        movwf   PORTB           ; display new digit               |B0
        DelayUS(4000-26)        ; 4-msecs including loop time     |B0
        clrf    PORTA           ; clear PORTA output latch        |B0
        clrf    INDF            ; setup PORTA all outputs         |B0
        DelayUS(4000)           ; 4-msecs                         |B0
        comf    INDF,F          ; setup PORTA all inputs          |B0
        movlw   b'10000000'     ; mask for digit select bit       |B0
        xorwf   DigSel,F        ; toggle b7 digit select bit      |B0
        goto    Display         ; loop forever                    |B0

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28th November 2007, 03:26 AM	(permalink)
dalmation	thanks- I will. Not WORST case, though- the problem with the eeproms powering down to sleep mode doesnt happen with 7999/1 delays (which was the initial problem). I just need to figure out exatly what it is about this new setup that has allowed it to work- then I can hopefully keep that aspect the same, but fix the display. Its 2am here- I'll get some sleep and continue tomorrow. -Thanks again. -Dal.