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Connecting CPLD to optical switch

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sul

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Hi All,
I need to connect an SN 1 to 1 optical latching switch to a CPLD.

The switch is JDS uniphase SN series switch and Cypress delta 39K series CPLD

Any help will be highly appreciated.

-Sul
 

I think CPLD can only interface with a digital signal. Is the switch controlled by digital signal?
 

Thanks for the reply,

Yes, this is a digital switch.

Can you guide me as to how to inteface then?
 

Hi, sul:

CPLD is a programmable device. It has many IO pins.

If the CPLD will be designed by you, you can link any IO to the switch and design the internal logic to control your switch.

But if the CPLD is designed by others and already programmed, you have to check the designer about each pin's function.

Hope this helps.
 

Thanks so much.

The CPLD will be designed by me. But the problem is of I/O compatibility.

The switch requires 5V 20ms DC pulse to operate while the CPLD supports 3.3V, 2.5V,1.8V, and 1.5V I/O capability.

What are the ways to connect such pins?

-Sul



dll_embed said:
Hi, sul:

CPLD is a programmable device. It has many IO pins.

If the CPLD will be designed by you, you can link any IO to the switch and design the internal logic to control your switch.

But if the CPLD is designed by others and already programmed, you have to check the designer about each pin's function.

Hope this helps.
Click to expand...
 

Hi, sul:

I happen to encounter the same problem for my previous project. Mine is a xilinx device. But the solution may apply to your case. When you want to output a 5V level, just tristate your IO pin. Otherwise, output 0.

The other safest way is to use an external level translator IC. (cheap 74 series)

( +5V--
( |
( | R|
( | |
|
3.3V IO----------------
 

I too faced a similar problem with a xilinx FPGA. I used IDT quickswitch devices.
Check \hxxp://www.idt.com/products/pages/Bus_Switches-QS3861.html
 

Thanks it_boy and dll_embed
Even I found some cheap translators from texas instruments

**broken link removed**


it_boy said:
I too faced a similar problem with a xilinx FPGA. I used IDT quickswitch devices.
Check \hxxp://www.idt.com/products/pages/Bus_Switches-QS3861.html
Click to expand...
 

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