Maple and STM32F103 dual simultaneous sampling

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Maple and STM32F103 dual simultaneous sampling

(71 posts) (14 voices)

Started 4 years ago by samtal
Latest reply from mbolivar

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atrabile
Member

Hello,

first of all, let me say the Maple is an awesome piece of hardware. I just got mine a couple of days ago and I fell in love :)

I'm developing a project needing dual simultaneous sampling and I wrote a small class that does just what I need.
Dual sampling works, and if I haven't messed up things in the last edit, it lets you choose between single/dual blocking/non-blocking modes, with dma transfers only. No interrupt function support (yet. If I'll need it, I'll look into it). Also, I'm not sure, but it may break the analogRead().

Here is the code:
http://pastebin.com/3YGWNLup
http://pastebin.com/S80mSeig
http://pastebin.com/Cs8T09sY
(for the demo to work, you need to link pin6 with pin2 and pin7 with pin0)

Feel free to use it as you wish.

As a side note, I see you don't use the ALIGN bit in the ADC registers and you just mask the results of adc_read...is there a reason for it?

Keep on with the great job :)

Posted 4 years ago #
mbolivar
LeafLabs

atrabile,

Thanks for the kind words and the code! This is great.

Edit: in answer to your question about alignment, no real reason why we did it that way. Sounds like a worthwhile change to make.

Posted 4 years ago #
anotherDJ
Member

Wow thanks atrabile, much appreciated!

so thats how you get dual ADC to work.. very cool!

thanks again.

Posted 4 years ago #
samtal
Member

Hello all kind experts (atrabile, mbolivar and others)

Thanks to and despite all kind experts who participate in this form, as the initiator of this form's issue, namely implementation of the dual ADC option of the STM32F103 with the Maple (NOT available on Arduino), I have to get back to my original request.

As a non C/C++ knowledgeable who still wish to use the Maple, I asked if someone would be willing to add the dual adc as a standard Maple language command, rather than just a C++ library.

Using the above C files probably necessitates some knowledge, which I (and additional armatures) do not have.
An alternative would be to add more detailed information on how to use the C++ files with the Maple to achieve the dual adc.

Thanks,
samtal

See also: http://wiki.leaflabs.com/index.php?title=Dual_Simultaneous_Sampling

Posted 4 years ago #
gbulmer
Moderator

mbolivar - please yield the value as right aligned from analogRead

1) It is very straightforward to explain to new users that there is finite resolution, and 12 bits is better than Arduino, so they can see why it matters. I think it will be harder to explain that there is only 12 significant bits, and the bottom 4 don't change.

2) left aligned data is also unhelpful because it means that the difference between signed and unsigned int matters in the first few hours of learning. It is an extra hurdle to overcome at a time when there are a lot of new things to discover anyway. The mind-boggling part (for a new user) is that big values are < than small values when they use int.

IMHO, the main advantage of left aligned data is when porting code between systems with different resolution ADC's; not a problem faced by STM32F10x users :-) Even then it can be an illusion as some algorithms need to be changed to account for different resolution anyway. For example optimal storage through bit-packing, filtering noise on lower bits, ...

Mapping to a specific range seems tricky in the general case anyway, but maybe I'm hungry and not thinking straight :-)

Posted 4 years ago #
mbolivar
LeafLabs

no worries! analogRead() is right aligned, now and forever.

Posted 4 years ago #
samtal
Member

Apology

In my previous post, I used the wording 'all kind experts' that, re-reading my post, sounds like 'all kind (of) experts' in a way that may sound offending.
I naturally did not mean that, I meant real sympathetic and caring experts that participate in the form.

I therefore ask again for help adding a standard Maple language command for the dual adc, rather than a C++ library which many armatures have difficulties using.
Thanks
samtal

Posted 4 years ago #
samtal
Member

Coming back to the dual adc issue after long waiting for support, I did my own search and found several solutions, but unfortunately non of which is complete.
One major issue is the large number of files having the same name, but no version number or date or other identification information. (like the adc.c and adc.h, but also some core files)
I have tried several .c and .h combinations, but there seem to be more files in the leaflabs/cores that do not match.

Can anyone please help me make a reasonable build that will work?

Is there a way or methodology to get some order in the Maple files like version numbers, author identification, serial numbers, dates, etc?

Posted 4 years ago #
poslathian
LeafLabs

samtal, you asked for language extensions rather than an external lib. Adding an external lib can be easier than you think. If it is written approperly, it can just be dropped into the "libraries" directory of your maple installation and included from the drop-down menu.

It may be straightforward to package one of the libraries someone has written so you can just drop it into your libraries directory. On the other hand, extending the language comes with quite a bit of overhead - design considerations, lots of arguing, testing, debugging, blah blah, and finally a new release. While I wont say the adc modules of libmaple and wirish wont be improved and extended over time (they will be) I would hold your breath for the exact feature you are asking for to be added to the next software release.

Posted 4 years ago #
poslathian
LeafLabs

I also meant to say that if a library will work for you, than I can take a look and see if we cant package one of the solutions posted here and on the wiki into a bundled lib.

Posted 4 years ago #
samtal
Member

Thank poslathian,
I understand and fully agree with your standpoint, with one exception: Language extension would have command descriptions and examples, while a lib or files I will need to investigate to find out the correct commands and formats to use (they normally have no user information).
I therefore searched and found at least one nice (matching?) pair of adc.c and adc.h that seem to have it all (https://github.com/leaflabs/libmaple/blob/master/libmaple/adc.c & adc.h).
I placed them (and replaced the original single-adc adc.c and adc.h) just where I found my Maple looks for them, which is \Maple\maple-ide-0.0.9\hardware\leaflabs\cores\maple.
I then wrote a minimal application (see below) and included the new files (although for some reason they seem to be included by default?), but I got a long list of errors that I try to clear, but I failed.
To make sure I do not mix files, I also tried to change the file names from adc to dadc (d for dual) but for no avail.
As I indicated in my prev post, there are many adc files on the net, written by various people, some are single adc, some others are dual (or triple), and there is no definite way to know which is a genuine pair of c and header, or what they do.
There is no make, version, or any ID on the files.
I am an old computer guy (have been there almost since the beginning, like 50 years back...retired and trying now to do some development work for new ideas), but I forgot the time when I programmed, and I need support.
If you have the time and patience, I’d appreciate your help.
Thanks,
samtal

The very basic program (there are several variations I have tried):
=======================
/*
#include "libmaple.h" //optional. Included in adc ?
#include "rcc.h" //optional
#include adc.h // or dadc.h
*/

int data;
int InputPin1 = 15; // select the input pin

void setup() {
}
void loop() {

//from dadc.c: uint16 adc_read(const adc_dev *dev, uint8 channel)
data= adc_read(ADC1,InputPin1);
SerialUSB.println(data);
delay(2000);

}

Posted 4 years ago #
samtal
Member

In my continued efforts to learn and implement dual adc, I encountered an issue that despite digging into the RM0008 and the Maple dual adc examples, I could not find a clear answer to.

There is a set of 3 registers to accommodate the 17 ADC channels sequence (ADC regular sequence registers (ADC_SQR1,2,3)) and the 'Dual Simultaneous only' bit in ADC_CR1.

One can set the sequence of the channels to be sampled, but there is only ONE such sequence register (for ADC1?), while there are two ADC !

How can one set the sequence for ADC2? Where is that sequence stored?
As stated in the RM0008, any sequence can be set to the ADC1 and ADC2).

As an example, I wish to set pairs of simultaneously sampled channels for ADC1 and ADC2 as follows:
ADC1: 1,3,5,7
ADC2: 2,4,6,8

I noticed in the core adc.c and .h files there is no function to set the sequence registeres (ADC_SQR1,2,3).

A brief explanation will be appreciated.

Thanks
samtal

Posted 4 years ago #
samtal
Member

I have been trying the Dual Simultaneous sequential DAC for some time, with mixed results.
Thanks to the latest adc.h which includes many (not all) dual adc functions, I could make progress. Thanks to whoever modified that header (?) and thanks to the great work with the dma header (Thanks to Marti and Michael Hope).
With all that said, I still cannot make it work as I wish.
(I do not attach my code on purpose. It is easier to make it right than to fix someone’s wrong code…)
Can anyone help with a working snippet with the following? (For Maple IDE)
I have 4 pairs of analog channels
Chan 8,9 pins 27,28
Chan 10,11 pins 15,16
Chan 12,13 pins 17,18
Chan 14,15 pins 19,20
I wish to convert them sequentially in dual simultaneous mode, each sequence of conversions by one software command or repetitively at a pre-set time interval.
(The transfer is supposed to go to a DMA 32-bits array, from where I will read the data and split the 32 bits into two 12 bits values).
samtal

(P.S. Why not add that Dual Simultaneous Mode as a Maple Example?)

Posted 4 years ago #
mbolivar
LeafLabs

There is a set of 3 registers to accommodate the 17 ADC channels sequence (ADC regular sequence registers (ADC_SQR1,2,3)) and the 'Dual Simultaneous only' bit in ADC_CR1.

One can set the sequence of the channels to be sampled, but there is only ONE such sequence register (for ADC1?), while there are two ADC !

How can one set the sequence for ADC2? Where is that sequence stored?
As stated in the RM0008, any sequence can be set to the ADC1 and ADC2).

Perhaps the confusion is that the section explaining the ADC registers in RM0008 gives the registers as offsets from a base address. This might lead you to think that there's e.g. only one ADC_SQR1. However, just as there are two ADCs, there are two regions in memory where their registers are stored. The precise base addresses are given in RM0008, Table 1.

Within libmaple, the register map for ADC1 may be accessed via the macro ADC1_BASE, and that for ADC2 via ADC2_BASE. So, for example, ADC2's regular sequence register 3 is ADC2_BASE->SQR3.

More information on reading and writing register maps can be obtained in the libmaple overview:

http://leaflabs.com/docs/libmaple/overview.html#register-maps

(I do not attach my code on purpose. It is easier to make it right than to fix someone’s wrong code…)

And it's impossible to guess what the problem might be without code, so I won't try ;).

Posted 4 years ago #
samtal
Member

Thanks for the information.
I naturally have learned all this since my previous post, but there still seem to be a problem which I am unable to resolve.
It's either something I do wrong, (misunderstand the RM0008) or a LibMaple bug.
My understanding (as stated in the RM) is that SQR3 takes care of the first 6 conversions, SQR2 is for conversions 7-12, and SQR1 is for conversions 13-17.
The adc.c function 'adc_set_sample_sequenceuses' use SQR1 and SQR2, while the first register should be SQR3, which is for sequences 1-6.

Now here is the problem I have: (which may relate to the above mentioned)
Within my code, I set the dual simultaneous adc sequence as follows: (just a short example. I use more channels and lots more functions)

set_dual_mode(ADC1,DADC_MODE_6); //6=Dual simult. only

ADC2->regs->SQR3=11; //This should set the first channel to be converted in ADC1
ADC1->regs->SQR3=12; //This should set the first to be converted in ADC2.

adc_set_reg_seqlen(ADC1, 1); //or a larger number
adc_set_reg_seqlen(ADC2, 1);

Reading back the registers:
SerialUSB.print(ADC1->regs->SQR3,BIN); //=10 bin (always)
SerialUSB.print("\t");
SerialUSB.println(ADC2->regs->SQR3,BIN); //=1011 bin (or any other number I set)

etc.

Looks like ADC1 with SQR3 (only) is never updated, regardless of what I do (I have tried different values, changed the order, etc.)
As can be seen, when I read back the SQR3 ADC1 and ADC2 registers, ADC2 always reads the correct channel with any number(s) I set in the sequence positions, while ADC1 SQR3 always reads 10 (binary), regardless of what I set (one channel or more).
If I use SQR2 (sequences 6-12) for dual, it looks OK, I get both ADC1 and ADC2 correct.
As I noted, this problem is only with ADC1 with SQR3.
Again, I may be doing something wrong, but to me this looks more like a bug.

samtal

And, as a sidenote, It would be nice if the sequence setting function 'adc_set_sample_sequence' (adc.h and adc.c) would have been modified to become more user friendly.
I may do it once I resolve the current issue and become more knowledgeable...

Posted 4 years ago #

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