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ファームウエアクローズループ　[jalv2_PIC] [編集]

アナログコンパレータ　ファームウエアクローズループ　AN700の jalv2化

;*********************************************************************
;* Filename: DeltaSig.asm
;*********************************************************************
;* Author: Dan Butler
;* Company: Microchip Technology Inc.
;* Revision: 1.00
;* Date: 02 December 1998
;* Assembled using MPASM V2.20
;*********************************************************************
;* Include Files:
;* p16C622.inc V1.01
;*********************************************************************
;* Provides two functions implementing the Delta Sigma A2D.
;* InitDeltaSigA2D sets up the voltage reference and comparator
;* in the "idle" state.
;* DeltaSigA2D runs the actual conversion. Results provided in
;* result_l and result_h.
;* See An700 figure 2 for external circuitry required.
;*********************************************************************
;* What's changed
;*
;* Date Description of change
;*
;*********************************************************************
-- chip setup
--#include <p16C622.inc>
--include 16C622
--include 16f628a
include 16f648a
--include chipdef_jallib

--cblock
--        result_l
--        result_h
--        counter:2
var byte result_l
var byte result_h
var byte*2 counter
-- const VOLATILE bit vcc_ch = 1
-- const VOLATILE bit pump_p = 2
--endc

alias               rp0                   is _rp0
alias               z                     is _z
--alias               c1out                 is cmcon_c1out
--alias               c1out                 is _c1out
--alias               cmcon,c1out             is cmcon_c1out_c1out
--alias               $+1                   is +1
--alias               goto $+1              is goto +1
;
;
;

Procedure InitDeltaSigA2D() is
assembler
--InitDeltaSigA2D
        bsf status,_rp0
        movlw 0xec
        movwf vrcon
        bcf porta,3 ;set comparator pin to output
--        bcf status,_rp0
        bcf status,rp0
        movlw 0x06 ;set up for 2 analog comparators with common reference
        movwf cmcon
--        return
end assembler
end procedure

;
; Delta Sigma A2D
; The code below contains a lot of nops and goto next instruction. These
; are necessary to ensure that each pass through the Elop1 takes the same
; amount of time, no matter the path through the code.
;
Procedure DeltaSigA2D() is
assembler
         LOCAL    elop1,comphigh,complow,eat2cycles,endelop1,eat5cycles,exit1
--DeltaSigA2D
        clrf counter
        clrf counter+1
        clrf result_l
        clrf result_h
        movlw 0x03 ; set up for 2 analog comparators with common reference
        movwf cmcon
elop1:
        btfsc cmcon_c1out ; is comparator high or low?
--        btfsc cmcon,c1out ; is comparator high or low?
        goto complow ; go the low route
comphigh:
        nop ; necessary to keep timing even
        bcf porta,3 ; porta.3 = 0
        incfsz result_l,f ; bump counter
        goto eat2cycles ;
        incf result_h,f ;
        goto endelop1 ;
complow:
        bsf porta,3 ; comparator is low
        nop ; necessary to keep timing even
        goto eat2cycles ; same here
eat2cycles:
        goto endelop1 ; eat 2 more cycles
endelop1:
        incfsz counter,f ; count this lap through the elop1.
        goto eat5cycles ;
        incf counter+1,f ;
        movf counter+1,w ;
        andlw 0x04 ; are we done? (we're done when bit2 of
--        btfsc status,_z ; the high order byte overflows to 1).
        btfsc status,z ; the high order byte overflows to 1).
        goto elop1 ;
        goto exit1
eat5cycles:
        goto +1 ; more wasted time to keep the elop1s even
--        goto $+1 ; more wasted time to keep the elop1s even
        nop ;
        goto elop1 ;
exit1:
        movlw 0x06 ; set up for 2 analog comparators with common reference
        movwf cmcon
--        return
end assembler
end procedure

--        end
InitDeltaSigA2D()

forever loop

DeltaSigA2D()

end loop