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Help with DIY CCD driver

  • Posts: 13
  • Thank you received: 2

Replied by Michael F. Toups on topic Help with DIY CCD driver

(Still using sudo.)

However, I think I found the key issue that is causing the read errors. It is that the ftdi library's ftdi_read_data and the D2XX FT_Read have very different behaviors. See developer.intra2net.com/mailarchive/html...i/2012/msg00149.html for example. Looks like we might need to implement some variant of the function given in the patch. However, that version appears to be windows specific but could easily be linux compatible (it uses windows timer function.)

Need to investigate further but I think this is the key issue; it looks like there should be an easy fix. I'll investigate further.
7 years 4 months ago #12723

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Replied by gehelem on topic Help with DIY CCD driver

this is the conclusion i was afraid of, as understanding the way this library works is much beyond my skills...
thank you for your help Mikael !
Gilles.
7 years 4 months ago #12724

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Replied by Michael F. Toups on topic Help with DIY CCD driver

I am trying a few things. I think this is solvable with a modified version of ftdi_read_data. If so we should be able to make this work. Might be a while before I can work some more on this.

Michael
7 years 4 months ago #12725

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Replied by gehelem on topic Help with DIY CCD driver

ok fine,
Here comes the cleaning time, many other points need to be checked, like binning and subframe
7 years 4 months ago #12726

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Replied by Michael F. Toups on topic Help with DIY CCD driver

Below are two diffs showing a quick mod that appears to take care of the "timing" issue due to the differences between D2XX and ftdi.

First I changed the calls to ftdi_read_data to ftdi_read_data_modified and created a new function ftdi_read_data_modified that continually calls ftdi_read_data until either too many attempts are made or all the data has been collected. This is a quick and dirty solution that appears to care of the problem. The number of tries and the usleep time are somewhat arbitrary and probably could be tuned. Not the cleanest solution, but this should allow your code to work with the ftdi library.

Michael

First in libcam84.h changes are
18,23d17
< #ifdef D2XX
< #else
< struct ftdi_context;
< int ftdi_read_data_modified(struct ftdi_context *ftdi, unsigned char *buf,  int size);
< #endif
<

and in libcam84.c the changes are
312c312
<       dwBytesRead=ftdi_read_data_modified(CAM8A,FT_In_Buffer,0);
---
>       dwBytesRead=ftdi_read_data(CAM8A,FT_In_Buffer,0);
338c338
<       dwBytesRead=ftdi_read_data_modified(CAM8A,FT_In_Buffer, 8*mdeltX);
---
>       dwBytesRead=ftdi_read_data(CAM8A,FT_In_Buffer, 8*mdeltX);
367c367
< 	  dwBytesRead=ftdi_read_data_modified(CAM8A,FT_In_Buffer, 2*mdeltX);
---
> 	  dwBytesRead=ftdi_read_data(CAM8A,FT_In_Buffer, 2*mdeltX);
965,980d964
< }
< 
< int ftdi_read_data_modified(struct  ftdi_context * ftdi, unsigned char * buf, int size)
< {
< 	int rsize = ftdi_read_data(ftdi, buf, size);
< 	int nsize=size-rsize;
< 	int retry=0;
< 	while((nsize>0)&(retry<20))
< 	{
< 		retry++;
< 		usleep(500);
<  //	     	 fprintf(stderr,"Try %d since %d<>%d \n",retry, rsize,size);
< 	        rsize = rsize+ftdi_read_data(ftdi, buf+rsize, nsize);
< 		nsize = size - rsize;
< 	}
< 	return rsize;
7 years 4 months ago #12731

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Replied by gehelem on topic Help with DIY CCD driver

very clever, it works for me quite well !
i can now run to baudrate 150 without errors
EDIT : never goes more than 1 or 2 retry, and ... 1us sleep...
Only first read often needs to wait
Last edit: 7 years 4 months ago by gehelem.
7 years 4 months ago #12732

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Replied by Michael F. Toups on topic Help with DIY CCD driver

Glad it works for you.

The old netbook I want to run the camera on gets lots of retries during a read at the 150 setting, but is successful. Sometimes goes to 4 or 5 retries. I had some hiccups with only 1 us of sleep where the read actually failed due to max number of retries but 10 us worked fairly well.
7 years 4 months ago #12734

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Replied by gehelem on topic Help with DIY CCD driver

My new Cam86 is working, and this is my very first picture with brand new indi driver !! i'm so excited!! :woohoo: :woohoo:
[url=
File Attachment:
][/url]
very "beta test" but this is the first step
The following user(s) said Thank You: Jasem Mutlaq
7 years 3 months ago #13430

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Replied by Michael F. Toups on topic Help with DIY CCD driver

speaking of the version indi_cam84_ccd on GitHub, did you incorporate the fix for the read? If not, I could probably create a branch today with those changes and request a "pull" back to the master branch.
7 years 3 months ago #13431

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Replied by gehelem on topic Help with DIY CCD driver

Sorry, i though i did, but i didn't...
I've commited, you'll find new version on github
Gilles.
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7 years 3 months ago #13432

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Replied by Michael F. Toups on topic Help with DIY CCD driver

Temporarily forked off a copy of your cam84 at github. I guess I would need you to give me access to create a branch on your repository and edit it. In any event, I expect once I finish the code we can merge back to a single branch.

I fixed the code to allow image sections to be read with working starting positions.

There are some additional changes and investigations in the code in my updates branch, some of these are highlighted in the readme file.

I am working on modifying the exposure timing logic (and there was probably a bug in the previous version for multi-second exposures.)
7 years 1 month ago #14848

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Replied by gehelem on topic Help with DIY CCD driver

hi, thank you
i'm working now on Cam86, il will come back to software later.
I've added you as a collaborator on my repository, if you accept the invitation, we can work on the same repository
See also the code from cam86 driver on my repo : we've found good improvments with reading process
Gilles,
7 years 1 month ago #14858

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