I got the solutio (i think.. hehe)
/*file doiscs.c
Compile by: `gcc -Wall -o doiscs doiscs.c -lpruio`
*/
#include "stdio.h"
#include "unistd.h"
#include "../c_wrapper/pruio.h"
#include "time.h"
int main(int argc, char **argv)
{
float n[256];
float v1[128];
float v2[128];
int i = 0;
pruIo *io = pruio_new(PRUIO_DEF_ACTIVE, 0x98, 0, 0);
//! create new driver structure
pruio_adc_setStep(io, 9, 1, 0, 0, 0);
// step 9, AIN-0
pruio_adc_setStep(io, 10, 2, 0, 0, 0);
// step 10, AIN-1
if (pruio_config(io, 128, 9<<10 , 156250, 4)){
printf("config failed (%s)\n", io->Errr);}
else {
if (pruio_rb_start(io)) printf("rb_start failed (%s)\n", io->Errr);
// start measurement
else{
sleep(1);
do{
if(io->DRam[0] == (i)){
n[i] = io->Adc->Value[i];
i=i+1;
}
}while(i < 256);
for(i = 0; i<=127; i++ ){
v1[i] = n[2*i];
v2[i] = n[2*i +1];
}
printf("adc1*************\n");
for(i=0; i<=127; i++){
printf("%f \n", v1[i]*1.8/65536);
}
printf("\n adc2*************\n");
for(i=0; i<=127; i++){
printf("%f \n ", v2[i]*1.8/65536);
}
}
}
pruio_destroy(io);
return 0;
}
The error is marked in yellow. The loop condition was considering the
garbage :D
Em segunda-feira, 6 de fevereiro de 2017 18:55:30 UTC+1, William Hermans
escreveu:
>
> Or better yet, get rid of the second loop entirely, and just print the
> values as you receive them. However, printf() *is* a system all that would
> definitely slow down your ADC read speeds. Unless you pipe the output of
> the application to a file. Which would not be healthy for the emmc, or
> sdcard you're running from.
>
> On Mon, Feb 6, 2017 at 10:52 AM, William Hermans <[email protected]
> <javascript:>> wrote:
>
>> Thinking about how to "throttle" reading from the ADC to get correct
>> values. A little more. One way you could potentially deal with that
>> situation could be to change both loops to a while() loop, and only
>> increment your loop index value if the ADC index value is greater than 0.
>> Or maybe test if the actual ADC index value is your loop index value +1.
>> With that said, actually you would only need to throttle the ADC read loop,
>> so the printing to screen loop could be left alone.
>>
>> However, this kind of loop would be very CPU intensive, but the problem
>> with with using usleep() is that technically htis is a system call, and in
>> addition to adding a hard coded delay, you're likely to also have some
>> system( between user space and kernel space ) non deterministic delay
>> penalty inured.
>>
>> On Mon, Feb 6, 2017 at 10:06 AM, William Hermans <[email protected]
>> <javascript:>> wrote:
>>
>>>
>>> On Mon, Feb 6, 2017 at 9:12 AM, Rodrigo Mesquita <[email protected]
>>> <javascript:>> wrote:
>>>
>>>> Mr, Willians, thanks for your answer.
>>>>
>>>> According to the lipruio's documentation, the variable io->DRam[0]
>>>> contains the index of the last ADC data read.
>>>>
>>>> About the part:
>>>>
>>>> do{
>>>> . . .
>>>> }while(io->DRam[0] < 126);
>>>>
>>>> This is inconsistent with:
>>>>
>>>> for(i = 0; i<=127; i++ ){
>>>> . . .
>>>> }
>>>>
>>>> ,
>>>>
>>>> the for is to print the values stored. The do-while is to read the
>>>> sample 1 to 126. the samples 0 and 127 are read before and after this
>>>> loop,
>>>> respectively.
>>>>
>>>> What are you sugestions to improve my code, Mr. Hermans?
>>>>
>>>
>>> Please, in the future do not email me personally. Please email to the
>>> group, so everyone can see the answer, as this may help others in the
>>> future. It also makes it much harder for me to follow the posts, and give a
>>> proper answer. Anyway . . .
>>>
>>> Assuming what you say is correct. Your loops are still off by two
>>> between them. The do / while() loop being 1 based( starts from 1 ) where
>>> the for() loop being zero based( starts from 0 ). To correct this most
>>> simply, change your for loop to i<=125, or i<126 if that is clearer for
>>> you.
>>>
>>> After that, starting from the top down.
>>>
>>> float n[256];
>>> int a[256];
>>> int i=0;
>>>
>>>
>>> float n[256]; is not needed. For this particular application you only
>>> need one float value for printing a voltage value in your printf()
>>> statement. In fact, in the future if you plan on expanding on this
>>> application you may wish to do away with float values entirely, send the
>>> raw PRU values to an external source( if that's what happens ) and let the
>>> external source do the heavy math. This makes what your beaglebone is doing
>>> more efficient, and if performance is needed can make a huge difference.
>>> Also, you can look into using fixed point numbers, but this would use more
>>> processor cycles than just sending out raw values.
>>>
>>> int a[256]; Assuming 128 samples, I might change this to: int
>>> channel_n[128]; ( n representing the actual channel you're reading from ),
>>> then do all the formatting in your printf() statement. If, and when you
>>> decide to print more than one channel worth of samples. This is however
>>> more a matter of semantics, but it'll also make your code much more
>>> readable. Again, you need to read the C standard for the compiler you're
>>> using. It does seem possible you're using a post C99 compiler as you're not
>>> initializing the variable i within the for() loop. Again, make sure your
>>> array has enough room for a NULL termination byte, if needed. Which
>>> wouldn't be of type byte, but instead of type int.
>>>
>>> The libpruio stuff TJF will be able to give you a much better answer on.
>>> As it's his code, and I know nearly nothing of the specifics for this code.
>>>
>>> if (pruio_rb_start(io)) printf("rb_start failed (%s)\n", io->Errr); //
>>> start measurement
>>> This is also a bit unclear to me, mostly due to not knowing the
>>> implementation, but I'd probably move this if() statement into a while
>>> statement. That way you can loop, and sleep 1 second between fails.
>>> Assuming the check fails more than once. Still it'd be clearer to at least
>>> me, which may not matter to you, or anyone else. Semantics . . . However,
>>> as it stands, if the check fails, you code will probably just exit. Maybe
>>> this is what you want ?
>>>
>>> As for your index values being "off" or just plain zero in some cases.
>>> The first thought that comes to mind is that you're trying to read from the
>>> ADC too fast. But again, I have no idea what TJF's code is doing, so this
>>> may not be possible. That would be the first place I'd look though, and in
>>> fact looking at your output, that seems very possible. As every value that
>>> has a garbage index value seems to be zero, or close to it. Ask TJF how you
>>> should throttle your loop. e.g. does he have something implemented in the
>>> library, or not.
>>>
>>> The rest of your code looks like it should work, so I'd clean up your
>>> code a bit, throttle the ADC reading loop how TJF suggests, and check your
>>> application output.
>>>
>>>
>>>
>>> On Mon, Feb 6, 2017 at 8:50 AM, William Hermans <[email protected]
>>> <javascript:>> wrote:
>>>
>>>>
>>>>
>>>> On Mon, Feb 6, 2017 at 4:21 AM, <[email protected] <javascript:>>
>>>> wrote:
>>>>
>>>>> Hello Mr. TJF
>>>>>
>>>>> First of All, thank you so much for providing support on real-time
>>>>> tasks using a low cost plataform.
>>>>> I'm trying to apply the libary "libpruio" to make a system for energy
>>>>> meansurement using the beaglebone black. To do this, I need to enable 2
>>>>> ADC channels, set a sample time, fil a buffer with the samples and make
>>>>> some calculation that includes the FFT. I'm really newbie on
>>>>> microprocessors, but i wrote a simple C code. The idea of this code is
>>>>> just
>>>>> to make 128 samples os the two channels and print the values. Just it:
>>>>>
>>>>> #include "unistd.h"
>>>>> #include "../c_wrapper/pruio.h" // include header
>>>>> #include "time.h"
>>>>>
>>>>>
>>>>> //! The main function.
>>>>> int main(/*int argc, char **argv*/)
>>>>> {
>>>>> float n[256];
>>>>> int a[256];
>>>>> int i=0;
>>>>>
>>>>>
>>>>> pruIo *io = pruio_new(PRUIO_DEF_ACTIVE, 0x98, 0, 1); //! create new
>>>>> driver structure
>>>>> pruio_adc_setStep(io, 9, 1, 0, 0, 0);
>>>>> // step 9, AIN-0
>>>>> pruio_adc_setStep(io, 10, 2, 0, 0, 0);
>>>>>
>>>>>
>>>>> if (pruio_config(io, 128, 9<<10 , 156250, 4)){ // upload (default)
>>>>> settings, start IO mode
>>>>> printf("config failed (%s)\n", io->Errr
>>>>> );}
>>>>> else {
>>>>>
>>>>>
>>>>> if <span style="color:rgb(102,
>>>>>
>>>>>
--
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