📄 dmacont.lst
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DMACONT PAGE 1
1 ;********************************************************************
2 ;
3 ; Author : ADI - apps www.analog.com/MicroConverter
4 ;
5 ; Date : October 2003
6 ;
7 ; File : DMAcont.asm
8 ;
9 ; Description : performs continuous mode DMA conversions on a
10 ; single ADC channel at 104KSPS
11 ; Debugger or emulator must be used to view results.
12 ;
13 ;********************************************************************
14
15 $MOD842 ; use 8052&ADuC842 predefined symbols
16
0040 17 DMACOUNT EQU 64 ; number of AD readings to take
0010 18 DMAINIT EQU 10h ; top nibble of DMAINIT = ADC channel
19
20 ;____________________________________________________________________
21 ; DEFINE VARIABLES IN INTERNAL RAM
---- 22 DSEG
0060 23 ORG 0060h
0060 24 DMASTOPH: DS 1 ; DMA stop address hi byte
0061 25 DMASTOPL: DS 1 ; DMA stop address lo byte
26
27 ;____________________________________________________________________
28 ; DEFINE SEGMENT OF EXTERNAL RAM
---- 29 XSEG
0000 30 ORG 000000h
0000 31 DMASTART: DS DMACOUNT*2 ; location for DMA results
0080 32 DMASTOP: DS 4 ; location for DMA stop sequence
33
34 ;____________________________________________________________________
35 ; BEGINNING OF CODE
---- 36 CSEG
0000 37 ORG 0000h
0000 02004B 38 JMP MAIN ; jump to main program
39
40 ;____________________________________________________________________
41 ; INTERRUPT VECTOR SPACE
0033 42 ORG 0033h ; (ADC ISR)
0033 C2DD 43 CLR CCONV ; stop conversions
0035 C3 44 CLR C ; clear C to indicate DMA done
0036 32 45 RETI
46
47 ;====================================================================
48 ; MAIN PROGRAM
004B 49 ORG 004Bh
004B 50 MAIN:
51
52 ; PRECONFIGURE external RAM for DMA capture on a single channel...
004B 75EF00 53 MOV ADCCON1,#00h ; set MD1, MD0 TO 0
54
004E 900080 55 MOV DPTR,#DMASTOP ; store DMASTOP 16bit value..
0051 858261 56 MOV DMASTOPL,DPL ; ..as a high byte & low byte
0054 858360 57 MOV DMASTOPH,DPH ; (for use in GETSTOPFLAG subr)
0057 900000 58 MOV DPTR,#DMASTART ; set DPTR to DMASTART address
DMACONT PAGE 2
005A 7410 59 SETUP: MOV A,#DMAINIT ; set up x-mem with init value
005C F0 60 MOVX @DPTR,A
005D A3 61 INC DPTR
005E E4 62 CLR A ; clear second byte
005F F0 63 MOVX @DPTR,A
0060 A3 64 INC DPTR
0061 12008B 65 CALL GETSTOPFLAG ; C cleared if DPTR>=DMAEND
0064 40F4 66 JC SETUP
67
0066 7410 68 MOV A,#DMAINIT ; "dummy" DMA location..
0068 F0 69 MOVX @DPTR,A ; ..to preceed stop command
0069 A3 70 INC DPTR
006A E4 71 CLR A
006B F0 72 MOVX @DPTR,A
006C A3 73 INC DPTR
74
006D 74F0 75 MOV A,#0F0h ; DMA stop command
006F F0 76 MOVX @DPTR,A
77
78 ; CONFIGURE ADC for DMA conversion...
79
0070 75D200 80 MOV DMAL,#0 ; start address for DMA operation
0073 75D300 81 MOV DMAH,#0 ; (must write DMA registers in this
0076 75D400 82 MOV DMAP,#0 ; order: DMAL, DMAH, DMAP)
83
0079 75D840 84 MOV ADCCON2,#040h ; enable DMA mode
007C 75EFAC 85 MOV ADCCON1,#0ACh ; 9.5us conv+acq time
86
007F D2AF 87 SETB EA ; enable interrupts
0081 D2AE 88 SETB EADC ; enable ADC interrupt
89
90 ; LAUNCH DMA conversion... when complete, ADC interrupt will clear C
91
0083 D2DD 92 SETB CCONV ; start continuous ADC conversions
0085 D3 93 SETB C
0086 40FE 94 JC $ ; wait for DMA to finish
95
0088 00 96 NOP ;.................................... SET BREAKPOINT HERE
97
98 ; REPEAT entire program...
99
0089 80C0 100 JMP MAIN
101
102 ;____________________________________________________________________
103 ; SUBROUTINE
104
008B 105 GETSTOPFLAG: ; clears C if DPTR>=DMASTOP
008B D3 106 SETB C
008C E583 107 MOV A,DPH
008E B56005 108 CJNE A,DMASTOPH,RET1 ; C cleared if DPH>=DMASTOPH
0091 E582 109 MOV A,DPL
0093 B56100 110 CJNE A,DMASTOPL,RET1 ; C cleared if DPL>=DMASTOPL
0096 22 111 RET1: RET
112
113 ;____________________________________________________________________
114
115 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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