📄 dmacont.lst
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DMACONT PAGE 1
1 ;********************************************************************
2 ;
3 ; Author : ADI - apps www.analog.com/MicroConverter
4 ;
5 ; Date : 7 September 1999
6 ;
7 ; File : DMAcont.asm
8 ;
9 ; Description : performs continuous mode DMA conversions on a
10 ; single ADC channel at 153.6KSPS (assuming an
11 ; 11.0592MHz Mclk).
12 ; Debugger or emulator must be used to view results.
13 ;
14 ;********************************************************************
15
16 $MOD812 ; use 8052&ADuC812 predefined symbols
17
0040 18 DMACOUNT EQU 64 ; number of AD readings to take
0010 19 DMAINIT EQU 10h ; top nibble of DMAINIT = ADC channel
20
21 ;____________________________________________________________________
22 ; DEFINE VARIABLES IN INTERNAL RAM
---- 23 DSEG
0060 24 ORG 0060h
0060 25 DMASTOPH: DS 1 ; DMA stop address hi byte
0061 26 DMASTOPL: DS 1 ; DMA stop address lo byte
27
28 ;____________________________________________________________________
29 ; DEFINE SEGMENT OF EXTERNAL RAM
---- 30 XSEG
0000 31 ORG 000000h
0000 32 DMASTART: DS DMACOUNT*2 ; location for DMA results
0080 33 DMASTOP: DS 4 ; location for DMA stop sequence
34
35 ;____________________________________________________________________
36 ; BEGINNING OF CODE
---- 37 CSEG
0000 38 ORG 0000h
0000 02004B 39 JMP MAIN ; jump to main program
40
41 ;____________________________________________________________________
42 ; INTERRUPT VECTOR SPACE
0033 43 ORG 0033h ; (ADC ISR)
0033 C2DD 44 CLR CCONV ; stop conversions
0035 C3 45 CLR C ; clear C to indicate DMA done
0036 32 46 RETI
47
48 ;====================================================================
49 ; MAIN PROGRAM
004B 50 ORG 004Bh
004B 51 MAIN:
52
53 ; PRECONFIGURE external RAM for DMA capture on a single channel...
004B 75EF00 54 MOV ADCCON1,#00h ; set MD1, MD0 TO 0
55
004E 900080 56 MOV DPTR,#DMASTOP ; store DMASTOP 16bit value..
0051 858261 57 MOV DMASTOPL,DPL ; ..as a high byte & low byte
0054 858360 58 MOV DMASTOPH,DPH ; (for use in GETSTOPFLAG subr)
DMACONT PAGE 2
0057 900000 59 MOV DPTR,#DMASTART ; set DPTR to DMASTART address
005A 7410 60 SETUP: MOV A,#DMAINIT ; set up x-mem with init value
005C F0 61 MOVX @DPTR,A
005D A3 62 INC DPTR
005E E4 63 CLR A ; clear second byte
005F F0 64 MOVX @DPTR,A
0060 A3 65 INC DPTR
0061 12008B 66 CALL GETSTOPFLAG ; C cleared if DPTR>=DMAEND
0064 40F4 67 JC SETUP
68
0066 7410 69 MOV A,#DMAINIT ; "dummy" DMA location..
0068 F0 70 MOVX @DPTR,A ; ..to preceed stop command
0069 A3 71 INC DPTR
006A E4 72 CLR A
006B F0 73 MOVX @DPTR,A
006C A3 74 INC DPTR
75
006D 74F0 76 MOV A,#0F0h ; DMA stop command
006F F0 77 MOVX @DPTR,A
78
79 ; CONFIGURE ADC for DMA conversion...
80
0070 75D200 81 MOV DMAL,#0 ; start address for DMA operation
0073 75D300 82 MOV DMAH,#0 ; (must write DMA registers in this
0076 75D400 83 MOV DMAP,#0 ; order: DMAL, DMAH, DMAP)
84
0079 75D840 85 MOV ADCCON2,#040h ; enable DMA mode
007C 75EF64 86 MOV ADCCON1,#064h ; 6.51us conv+acq time
87
007F D2AF 88 SETB EA ; enable interrupts
0081 D2AE 89 SETB EADC ; enable ADC interrupt
90
91 ; LAUNCH DMA conversion... when complete, ADC interrupt will clear C
92
0083 D2DD 93 SETB CCONV ; start continuous ADC conversions
0085 D3 94 SETB C
0086 40FE 95 JC $ ; wait for DMA to finish
96
0088 00 97 NOP ;.................................... SET BREAKPOINT HERE
98
99 ; REPEAT entire program...
100
0089 80C0 101 JMP MAIN
102
103 ;____________________________________________________________________
104 ; SUBROUTINE
105
008B 106 GETSTOPFLAG: ; clears C if DPTR>=DMASTOP
008B D3 107 SETB C
008C E583 108 MOV A,DPH
008E B56005 109 CJNE A,DMASTOPH,RET1 ; C cleared if DPH>=DMASTOPH
0091 E582 110 MOV A,DPL
0093 B56100 111 CJNE A,DMASTOPL,RET1 ; C cleared if DPL>=DMASTOPL
0096 22 112 RET1: RET
113
114 ;____________________________________________________________________
115
116 END
VERSION 1.2h ASSEMBLY COMPLETE, 0 ERRORS FOUND
DMACONT PAGE 3
ADCCON1. . . . . . . . . . . . . D ADDR 00EFH PREDEFINED
ADCCON2. . . . . . . . . . . . . D ADDR 00D8H PREDEFINED
CCONV. . . . . . . . . . . . . . B ADDR 00DDH PREDEFINED
DMACOUNT . . . . . . . . . . . . NUMB 0040H
DMAH . . . . . . . . . . . . . . D ADDR 00D3H PREDEFINED
DMAINIT. . . . . . . . . . . . . NUMB 0010H
DMAL . . . . . . . . . . . . . . D ADDR 00D2H PREDEFINED
DMAP . . . . . . . . . . . . . . D ADDR 00D4H PREDEFINED
DMASTART . . . . . . . . . . . . X ADDR 0000H
DMASTOP. . . . . . . . . . . . . X ADDR 0080H
DMASTOPH . . . . . . . . . . . . D ADDR 0060H
DMASTOPL . . . . . . . . . . . . D ADDR 0061H
DPH. . . . . . . . . . . . . . . D ADDR 0083H PREDEFINED
DPL. . . . . . . . . . . . . . . D ADDR 0082H PREDEFINED
EA . . . . . . . . . . . . . . . B ADDR 00AFH PREDEFINED
EADC . . . . . . . . . . . . . . B ADDR 00AEH PREDEFINED
GETSTOPFLAG. . . . . . . . . . . C ADDR 008BH
MAIN . . . . . . . . . . . . . . C ADDR 004BH
RET1 . . . . . . . . . . . . . . C ADDR 0096H
SETUP. . . . . . . . . . . . . . C ADDR 005AH
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