Hi!
To sample as fast as possible you've to configure your steps first, using
function AdcUdt::setStep:
- Avaraging = 0
- SaD = 0
- OpD = 0
Then you call PruIo::config()
- Samp is the number of samples to fetch. In MM mode it's the size of
the buffer, libpruio stops when the buffer is full. In RB mode the buffer
is used as a ring buffer an sampling continues. Samp <= 1 means single mode
(no accurate timing = variable sampling rate).
- Tmr is the number of ns between the samples (MM and RB mode only), so
that's the parameter to specify the sampling rate.
io_input.c uses single mode. Better start with rb_file.c example:
/** \file rb_file.c
\brief Example: fetch ADC samples in a ring buffer and save to file.
This file contains an example on how to use the ring buffer mode of
libpruio. A fixed step mask of AIN-0, AIN-1 and AIN-2 get configured
for maximum speed, sampled in to the ring buffer and from there saved
as raw data to some files.
Licence: GPLv3
Copyright 2014-2015 by Thomas{ dOt ]Freiherr[ At ]gmx[ DoT }net
Thanks for C code translation: Nils Kohrs (nils.kohrs [at] gmail.com)
Compile by: `gcc -Wall -o rb_file rb_file.c -lpruio -lprussdrv`
\since 0.2.0.2
*/
#include "unistd.h"
#include "time.h"
#include "stdio.h"
#include "../c_include/pruio.h"
//! The main function.
int main(int argc, char **argv)
{
const uint32 tSamp = 123401; //!< The number of samples in the files
(per step).
const uint32 tmr = 5000; //!< The sampling rate in ns (5000 -> 200
kHz).
const uint32 NoStep = 3; //!< The number of active steps (must match
setStep calls and mask).
const uint32 NoFile = 2; //!< The number of files to write.
const char *NamFil = "output.%u"; //!< The output file names.
struct timespec mSec;
mSec.tv_nsec=1000000;
pruIo *io = pruio_new(PRUIO_DEF_ACTIVE, 0x98, 0, 1); //! create new
driver
if (io->Errr){
printf("constructor failed (%s)\n", io->Errr); return 1;}
do {
if (pruio_adc_setStep(io, 9, 0, 0, 0, 0)){ // step 9, AIN-0
printf("step 9 configuration failed: (%s)\n", io->Errr); break;}
if (pruio_adc_setStep(io,10, 1, 0, 0, 0)){ // step 10, AIN-1
printf("step 10 configuration failed: (%s)\n", io->Errr); break;}
if (pruio_adc_setStep(io,11, 2, 0, 0, 0)){ // step 11, AIN-2
printf("step 11 configuration failed: (%s)\n", io->Errr); break;}
uint32 mask = 7 << 9; //!< The active steps (9 to 11).
uint32 tInd = tSamp * NoStep; //!< The maximum total index.
uint32 half = ((io->ESize >> 2) / NoStep) * NoStep; //!< The maximum
index of the half ring buffer.
if (half > tInd){ half = tInd;} // adapt size for small files
uint32 samp = (half << 1) / NoStep; //!< The number of samples (per
step).
if (pruio_config(io, samp, mask, tmr, 0)){ // configure driver
printf("config failed (%s)\n", io->Errr); break;}
if (pruio_rb_start(io)){
printf("rb_start failed (%s)\n", io->Errr); break;}
uint16 *p0 = io->Adc->Value; //!< A pointer to the start of the ring
buffer.
uint16 *p1 = p0 + half; //!< A pointer to the middle of the ring
buffer.
uint32 n; //!< File counter.
char fName[20];
for(n = 0; n < NoFile; n++){
sprintf(fName, NamFil, n);
printf("Creating file %s\n", fName);
FILE *oFile = fopen(fName, "wb");
uint32 i = 0; //!< Start index.
while(i < tInd){
i += half;
if(i > tInd){ // fetch the rest(no complete chunk)
uint32 rest = tInd + half - i;
uint32 iEnd = p1 >= p0 ? rest : rest + half;
while(io->DRam[0] < iEnd) nanosleep(&mSec, NULL);
printf(" writing samples %u-%u\n", tInd -rest, tInd-1);
fwrite(p0, sizeof(uint16), rest, oFile);
uint16 *swap = p0;
p0 = p1;
p1 = swap;
}
if(p1 > p0) while(io->DRam[0] < half) nanosleep(&mSec, NULL);
else while(io->DRam[0] > half) nanosleep(&mSec, NULL);
printf(" writing samples %u-%u\n", i-half, i-1);
fwrite(p0, sizeof(uint16), half, oFile);
uint16 *swap = p0;
p0 = p1;
p1 = swap;
}
fclose(oFile);
printf("Finished file %s\n", fName);
}
} while(0);
pruio_destroy(io);
return 0;
}
BR
--
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