Hello,

 

Thank you for your mail. 

The problem is that I do not know any FreeBasic whatsoever ...  so I am trying 
hard to figure out the C equivalent. 

 

I think I got it to work now, I can sample at 7us for a single channel in RB 
mode.  

 

I would like to ask about the parameters of pruio_new(ACT, Av, OpD, SaD) :

 

-       Av: documentation says it is averaging.     Say, if I set this to 4, 
does it mean that -during one sampling time- each AINx gives one output (each), 
but this output is the mean of 4 samples taken from the same AIN? E.g. for 
Av=4:    AIN0_out = (AIN0_sample1+ …+AIN0_sample4)/4  and:    AIN1_out = 
(AIN1_sample1+ …+AIN1_sample4)/4 and ……  ?

 

-       OpD: open delay : “number of clock cycles the ADC waits between setting 
the step configuration and sending the start of conversion signal” --- Is this 
the so called ‘settling time’ of a DAQ device, i.e., the time we wait for the 
internal capacitor to charge/for the voltage signal to settle before we 
actually make a measurement? 

 

 

-       SaD : “sets the sample delay, which is the number of clock cycles the 
ADC waits before starting (the width of the start of conversion signal). It 
specifies the number of clock cycles between the single conversion processes” – 
I do not see why this should not be always 0…. Is there a reason for it, maybe 
it defines how far in time the measurements will be made if averaging ‘Av’ is 
used?

 

Sorry if the questions are somewhat stupid –  if you had some good sources 
where these are taken from/understood/explained, I’d appreciate.

 

 

Thanks a lot!

 

Best regards,

Istvan

 

 

 

From: TJF [mailto:[email protected]] 
Sent: 27 October 2015 19:12
To: BeagleBoard
Cc: [email protected]; [email protected]
Subject: Re: beaglebone black ADC via Bonescript slow? - how to improve or 
alternatives?

 

Hi!

Am Dienstag, 27. Oktober 2015 19:16:51 UTC+1 schrieb Istvan Biro:

   Hello,

 

Thank you for your reply! 

 

I have installed the package successfully and am now looking at the code 
(examples) to figure out the usage. I find this very hard… now I am looking at 
example io_input.c, but there is very little comments included and I do not 
understand most of the code (e.g., commands like FD_ZERO(&set);

  FD_SET(STDIN_FILENO, &set);


FD_... function family is C stuff (I'm no C expert). Look them up in C 
documentation.

  -- or why pruio_new(PRUIO_DEF_ACTIVE, 0x98, 0, 1) has these arguments, etc… 
). 


Sorry, this is a bug (wrong parameter order). For full speed us

pruio_new(PRUIO_DEF_ACTIVE, 0, 0, 0)

 

Is there any description for more naive users?  I mean something to explain how 
to use this library?


Did you find the online documentation 
<http://users.freebasic-portal.de/tjf/Projekte/libpruio/doc/html/> ?

Tasks I would like to do: 

--switch to MM or RB, 

-- read analog values (how to access buffer?) – theoretically 3 functions…


MM mode is used in example triggers.bas (FreeBASIC only since it uses graphics).

RB mode example isn't included in version 0.2. You can find pre-published code 
by searching this forum for "rb_file". Find also information on how to 
re-compile version 0.2 in order to use rb_file (and trigger.bas) at full speed.

BR

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