;************************************************************************
;                                                                       *
;   Filename:      delay10.asm                                          *
;   Date:          22/1/08                                              *
;   File Version:  1.2                                                  *
;                                                                       *
;   Author:        David Meiklejohn                                     *
;   Company:       Gooligum Electronics                                 *
;                                                                       *
;************************************************************************
;                                                                       *
;   Architecture:  Baseline PIC                                         *
;   Processor:     any                                                  *
;                                                                       *
;************************************************************************
;                                                                       *
;   Files required: none                                                *
;                                                                       *
;************************************************************************
;                                                                       *
;   Description:    Variable Delay : N x 10ms (10ms - 2.55s)            *
;                                                                       *
;       N passed as parameter in W reg                                  *
;       exact delay = W x 10.015ms                                      *
;                                                                       *
;   Returns: W = 0                                                      *
;   Assumes: 4MHz clock                                                 *
;                                                                       *
;************************************************************************

    #include    <p12F509.inc>   ; any baseline device will do

    GLOBAL      delay10_R


;***** VARIABLE DEFINITIONS
        UDATA
dc1     res 1                   ; delay loop counters
dc2     res 1
dc3     res 1


;***** Subroutines
        CODE

delay10_R                       ; delay W x 10ms
        banksel dc3             ; -> ?+1+Wx(3+10009+3)-1+4 = Wx10.015ms
        movwf   dc3             
dly2    movlw   .13             ; repeat inner loop 13 times
        movwf   dc2             ; -> 13x(767+3)-1 = 10009 cycles
        clrf    dc1             ; inner loop = 256x3-1 = 767 cycles
dly1    decfsz  dc1,f           
        goto    dly1
        decfsz  dc2,f           ; end middle loop
        goto    dly1            
        decfsz  dc3,f           ; end outer loop
        goto    dly2

        retlw   0

        END