Hi everybody.
I am currently working on an project where I want to store a sine wave
lookup table
within the 2048 bytes of ERAM of the AT89C51AC3. Thus before my code
enters the main()
it initializes this array like that:
__xdata unsigned char
dac_values[128]={128,134,140,146,152,158,165,170,176,182,188,193,198,203,208,213,218,222,226,230,234,
237,240,243,245,248,250,251,253,254,254,255,255,255,254,254,253,251,250,248,245,243,
240,237,234,230,226,222,218,213,208,203,198,193,188,182,176,170,165,158,152,146,140,
134,128,121,115,109,103,97,90,85,79,73,67,62,57,52,47,42,37,33,29,25,21,18,15,12,10,
7,5,4,2,1,1,0,0,0,1,1,2,4,5,7,10,12,15,18,21,25,29,33,37,42,47,52,57,62,67,73,79,85,
90,97,103,109,115,121};
Curiously the data in that array gets corrupted. For testing purposes I
let the µC send the contents of the array via UART
to my computer. What I get looks like this:
128 134 140 146 152 158 165 170 176 182 188 193 198 203 208 213 218 222
226 230 234 237 240 243 245 248 250 251 253 254 254
255 255 255 254 254 253 251 250 248 245 243 240 237 234 230 226 222 218
213 208 203 198 193 188 182 176 170 165 158 152 146
140 134 128 121 115 109 103 97 90 85 79 73 67 62 57 52 47 42 37 33 29 25
21 18 15 12 10 7 5 0 0 4 96 8 0 16 16 8 0 16 0 1 2
0 2 0 0 0 0 0 0 66 0 0 17 0 0 0 32 0 80 4 2 132 20 0
As you can see the last few elements starting at 12, 10, 7, 5, ..... are
corrupted.
Now...I read something in the sdcc manual about startup code and MPAGE
SFR at 0x92 or in case of an µC with dual data pointers
(as the AT89C51AC3) reassembling the crtxinit.asm with DUAL_DPTR = 1.
Do you guys think my problem cam be solved by one of the last mentioned
things?
If so...I would be very thankful if you could give me some advice in
solving my problem. Like how to reassemble crtxinit.asm.
Sure...giving it to an assembler....but where to put the resulting
output file?
Hope you can help me on this problems.
Markus
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