CCD-world: Optical Link in CCD Controller

Fri Sep 24 16:40:59 CLT 1999

The following was posted to CCD-world:

Hello everybody,
	here at the TNG for our "new generation CCD controller" we have been using the 1.25 GBit/s HP chip-set:  N.1 HDMP 1022 (21 bits data parallel-to-serial)
N.1 HDMP1024 (21 bits serial-to-parallel). 
As fiber optic link we adopted the HFBR 5303.
We use the system in full duplex, because we do all digital sequences on a PCI board (that has a Motorola DSP 56302) and transmit them and all programming signals to the electronics located near the dewar.    
With this fast link we are able to readout, in principle, 50 video-channels (of 1 Mpixel/s) simultaneously.
Our analog board (that includes four channel CDS with a 2.5 microsec of RC) allows 400 Kpixel/s per channel and thus we can drive many analog boards (for mosaics).  
You will read more on the 4th ESO CCD WORKSHOP PROCEEDINGS.

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Giovanni Bonanno, Osservatorio Astrofisico di Catania
Viale A. Doria, 6,    
I-95125 Catania, Italy
Tel. +39 95-7332204, 
Fax. +39 95-330592
e-mail: gbo at sunct.ct.astro.it
CCD Lab web page: http://www.ct.astro.it/ccdlab/index.html
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*********** REPLY SEPARATOR ***********

On 22/09/99, at 13.13, Bruce Atwood wrote: 

>The following was posted to CCD-world:
>
>We have been using AMD (Advanced Micro Devices) TAXI chips
>(AM7969/AM7968) for the parallel to serial conversion and HP fiber parts
>(HFBR 2416/HFBR 1414) with ST connectors for over ten years.  We have a
>120 Mbit/sec bi-directional link which is fully synchronous (only one
>clock in the whole system).  The circuitry between the TAXI's and the
>fiber parts is from the HP's Application Bulletin 78.
>
>Yes we do have the "sequencer" at the computer end of the fiber link
>(hence the need for high speed in both directions)  We don't need a
>reset in the telescope mounted electronics because it just does what it
>is told to do by the sequencer data coming up the fiber.
>
>Bon chance.
>
>
>
>DE KAT Jean DAPNIA wrote:
>> 
>> The following was posted to CCD-world:
>> 
>> Hello everybody,
>> 
>> as discussed in the ESO WorkShop, I find that will be great to present in
>> this forum some solutions and not only questions. (Maybe this would be more
>> efficient than some WorkShop roundtables ...)
>> 
>> Then I start with a common problem for all CCD controllers developpers i.e.
>> the optical link to evacuate the CCDs data.
>> 
>> I have recensed in the last 2 years the available optical links in the
>> market because I didn't want to develop a new one for MegaCam (for time to
>> develop and maintenance reasons).
>> 
>> I needed a performant link (100MB/s), easy to implement in my custom CCD
>> controller, without any high level software driver (as in FiberChannel,
>> gigabitEthernet, ...) and directly pluggable into commercial VME boards.
>> 
>> I found only 2 links like that. One from Systran is called the Simplex Link,
>> has a PMC form factor at both side and implement a FPDP->Fiber->FPDP
>> protocol. (FPDP = simple parallel communication protocol).
>> Unfortunately, this products seems virtual since it exists only on the web
>> for many months ...
>> 
>> The other is the SLink that I finally adopted. We plan to plug it into a
>> Motorola PPC board (VME board with PCI as internal bus).
>> 
>> Here is a description of SLink:
>> 
>> - SLink was developed at CERN (Particle Physics in Geneve). When we need
>> some optical links for our controllers, they need thousand of links for some
>> experiments...
>> - SLink won't vanish in few years; it is now sold by private companies and
>> the CERN experiments will need it for at least the next 10-20 years.
>> - SLink is not a common standard. Only the mechanics, the connector and the
>> protocol on this connector is defined. That allows users to benefit from
>> future laser/fiber/coding... technologies by just unplug the old link and
>> plug a new one.
>> - SLink allows transfers on fiber at rates > 100MB/s in one direction. There
>> is a second fiber but is used to secure dialog between emitter/receiver. It
>> can however be used but at a lower transfer rate. That doesn't matter in
>> most of our controllers where we have to download few commands to the
>> controller and upload large CCD data (except for those who believe in remote
>> CCD sequencing ...).
>> - On the controller side, SLink is seen as a synchronous 32 bits Fifo. That
>> is to say that the controller developer has just to implement somewhere the
>> SLink connector, to reserve the space for a SLink daugther board (PMC form
>> factor) and to interface its system to a 32 bits Fifo.
>> - On the other side of the fiber, we have to plug a same SLink board on a
>> adaptator. Adaptator for PMC, PCI, VME exist. A more compact board with a
>> SLink board merged with an PMC adaptator exists too.
>> - Various software drivers are already developped (except mine ... : we have
>> had to develop our driver because it didn't exist yet (PMC, VxWorks).
>> 
>> To summarize, SLink is easy to implement, performant, and there is nothing
>> to develop in VME crate.
>> The only drawback I found, is that you can't use it to send a reliable reset
>> to your controller. You need another channel just for that.
>> Note too that, in most of cases, the SLink will not be the speed limit of
>> the whole system. In my system for example, the PPC board is the 1st limit
>> with 89MB/s on PCI bus.
>> 
>> I think that SLink could be a good solution for most of us.
>> 
>> For more info, you can see the WebSites:
>> http://www.cern.ch/hsi/s-link/
>> http://www.systran.com/fibrextreme.htm
>> 
>> But maybe someone has another solution ?
>> 
>> Another question:
>> Is anybody happy with remote CCD sequencing (sequencer at the other end of
>> fiber) ? What are the performances in term of sequencing speed,
>> synchronisation, power dissipation ?
>> 
>> jdK
>> 
>> ******************************************
>> jean de Kat - Electronics Engineer
>> CEA-Saclay, Dapnia/Sei
>> 91191 Gif-sur-Yvette, FRANCE
>> Tel: 33 1 69 08 85 05   or  33 1 69 08 62 81
>> Fax: 33 1 69 08 31 47
>> Email: jean.de-kat at cea.fr
>> *********************
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>
>-- 
>Bruce Atwood
>Director
>Imaging Sciences Laboratory
>Astronomy Department
>The Ohio State University
>174 W. 18th Ave.
>Columbus, Ohio  43210-1106
>(614) 292 6279 (V)
>(614) 292 2928 (F)
>- -- CCD-world -- --
>CCD-world is fully moderated. Send posts to CCD-world at astro.ku.dk
>Standard replies will go to the list; address personal replies manually.
>For more information, please go to:  http://www.not.iac.es/CCD-world/
- -- CCD-world -- --
CCD-world is fully moderated. Send posts to CCD-world at astro.ku.dk
Standard replies will go to the list; address personal replies manually.
For more information, please go to:  http://www.not.iac.es/CCD-world/