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78 lines
1.4 KiB
78 lines
1.4 KiB
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/*
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* gertboard.c:
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* Simple test for the SPI bus on the Gertboard
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*
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* Hardware setup:
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* D/A port 0 jumpered to A/D port 0.
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*
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* We output a sine wave on D/A port 0 and sample A/D port 0. We then
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* copy this value to D/A port 1 and use a 'scope on both D/A ports
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* to check all's well.
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*
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <math.h>
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#define B_SIZE 200
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#undef DO_TIMING
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#include <wiringPi.h>
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#include <gertboard.h>
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int main (void)
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{
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double angle ;
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int i ;
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uint32_t x1 ;
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int buffer [B_SIZE] ;
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#ifdef DO_TIMING
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unsigned int now, then ;
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#endif
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printf ("Raspberry Pi Gertboard SPI test program\n") ;
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if (wiringPiSetupSys () < 0)
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return -1 ;
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if (gertboardSPISetup () < 0)
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return 1 ;
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// Generate a Sine Wave
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for (i = 0 ; i < B_SIZE ; ++i)
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{
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angle = ((double)i / (double)B_SIZE) * M_PI * 2.0 ;
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buffer [i] = (int)rint ((sin (angle)) * 127.0 + 128.0) ;
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}
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for (;;)
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{
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#ifdef DO_TIMING
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then = millis () ;
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#endif
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for (i = 0 ; i < B_SIZE ; ++i)
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{
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gertboardAnalogWrite (0, buffer [i]) ;
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#ifndef DO_TIMING
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x1 = gertboardAnalogRead (0) ;
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gertboardAnalogWrite (1, x1 >> 2) ; // 10-bit A/D, 8-bit D/A
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#endif
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}
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#ifdef DO_TIMING
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now = millis () ;
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printf ("%4d mS, %9.7f S/sample", now - then, ((double)(now - then) / 1000.0) / (double)B_SIZE) ;
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printf (" -> %9.4f samples/sec \n", 1 / (((double)(now - then) / 1000.0) / (double)B_SIZE)) ;
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#endif
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}
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return 0 ;
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}
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