Re: setup problems for PCVision + JAI CV-M1

["M.Stein" <matthias@gom.com>]

Hi Richard!

On Wed, 3 May 2000, Richard Beare wrote:

> 
> Incidentally, I'm still having no luck duplicating the NT config file
> under linux. In fact I can't really see how the cv-m1-20pll example was
> constructed.
> 
> I have been looking at the worksheets describing the programming of PLL
> mode and I cannot understand how the critical values are obtained.
> 
> for example. The windows config file for CV-M1 from the iti web site has
> the following values (1296x1026)
> 
>       HTotal = 454
>       HSync_Low = 67
>       HEqual_End = 32
>       Serration_Total = 388
>       VTotal = 1049
>       VSync_Low = 5
>       HSync_Pol_Lo
>       VSync_Pol_Lo
>       VGate_Start = 518
>       VGate_End = 11
>       HOffset = 233
>       HActive = 1526
>       VOffset = 5
>       VActive = 1031
> 
> The linux version has
> 
>      HTotal = 2048              # use value + 1 * 2
>      HSync_Low = 1              # use value + 1
>      HEqual_End = 1             # use value + 1
>      Serration_Total = 1024     # use value + 1
>      VTotal = 1050              # use value + 1 (half lines)
>      VSync_Low = 6              # use value + 1 (half lines)
>      HSync_Pol_Lo
>      VSync_Pol_Lo
>      VGate_Start = 2048         # use value + 1 (half lines)
>      VGate_End = 12             # use value + 1 (half lines)
> # width = HActive - HOffset % 4 == 0 !
>      HOffset = 277              # use value + 1
>      HActive = 1555             # use value + 1
> # height = VActive - VOffset
>      VOffset = 16               # use value + 1 
>      VActive = 1024             # use value + 1
> 
> If I compute HActive as described in the work sheet I get something like
> the windows value, but I can't see how the linux version should be
> computed.
> 
> I also notice that the divisible by 4 rule for HActive - HOffset doesn't
> seem to hold in the linux file.
> 
> I've found that I can decrease the linux HOffset by 16 to give the same
> horizontal resolution in both systems, but I have had no luck in getting
> more than 1024 lines under Linux. I think I'm looking in the wrong
> places because I don't understand the relationships between the contents
> of the two file types at all.
>

Oh, Oh, long time ago, that I have done this!

1. The horizontal and vertical resolution of the image is the difference
   between HActive - HOffset and VActive - VOffset. To increse it, you
   have to increse the Active value or to decrese the Offset value.

2. In my opinion, the HTotal, HSync_Low, HEqual_End, Serration_Total ...
   values are only important, if you want to generate a sync signal and
   send it to the camera (XTAL mode). This is not, what we do - we receive
   a sync signal and have to adjust the pll to it. So the important values
   are PLL_FDIV, PLL_RDIV, PLL_VCO ...
   So I think, the 2048, 1, 1, 1024 values in the config file are dummy
   ones.

No guarantee, that my thoughts are right...

					
					matthias