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16,141 Views
Registered: ‎06-04-2013

ML605 VCC 1.2V setting for FMC LPC / HPC (J63/64)

Hello,

 

Requirement :

I have a chip whose logic 1 is 1.2V and 0 is 0V. I'm planning to connect this chip with the ML605 board with a FMC-105 debug card.

 

So far done :

I made pin assignments in the UCF file and set the IOSTANDARD as LVCMOS12. I'm now hoping to get 1.2V for logic 1 at those pins.

 

Problem :

When I measure the volatage levels it measures 2.5V for logic 1. I read in couple of other threads that just setting IOSTANDARD to LVCMOS12 won't suffice. I should also configure the VCC pins of that bank to1.2V to acheive it.


I looked in a couple of documents hoping that there might be some jumpers positions I need to rearrange, but no help. Can someone please guide me how to do it ?

If this can't acheived by setting jumpers, how would I know which all pins are VCC on the FMC card ? Thanks in advance.

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9 Replies
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Historian
Historian
16,134 Views
Registered: ‎02-25-2008


@praveendath92 wrote:

Hello,

 

Requirement :

I have a chip whose logic 1 is 1.2V and 0 is 0V. I'm planning to connect this chip with the ML605 board with a FMC-105 debug card.

 

So far done :

I made pin assignments in the UCF file and set the IOSTANDARD as LVCMOS12. I'm now hoping to get 1.2V for logic 1 at those pins.

 

Problem :

When I measure the volatage levels it measures 2.5V for logic 1. I read in couple of other threads that just setting IOSTANDARD to LVCMOS12 won't suffice. I should also configure the VCC pins of that bank to1.2V to acheive it.


I looked in a couple of documents hoping that there might be some jumpers positions I need to rearrange, but no help. Can someone please guide me how to do it ?

If this can't acheived by setting jumpers, how would I know which all pins are VCC on the FMC card ? Thanks in advance.


You have to connect the proper supply voltage to a bank's VCCO pins. If you want 1.2V you need to connect a 1.2V supply!

----------------------------Yes, I do this for a living.
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16,131 Views
Registered: ‎06-04-2013

Can you give me some pointers to figure out the VCC pin(s) on the debug card ? I only see VADG, VCC3V3 and VCC_12P and many GND pins on it. But not VCC.

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Historian
Historian
16,126 Views
Registered: ‎02-25-2008


@praveendath92 wrote:

Can you give me some pointers to figure out the VCC pin(s) on the debug card ? I only see VADG, VCC3V3 and VCC_12P and many GND pins on it. But not VCC.


Without a schematic, and without the time to spend doing it, no.

 

It might turn out that the connection doesn't support 1.2V I/O. that's a limitation of the card design, not the FPGA itself.

----------------------------Yes, I do this for a living.
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16,113 Views
Registered: ‎06-04-2013

I just had a check. The card seem to support only 2.5V logic 1 :( 

Is there a way I can configure the board with VCC 1.2V. I don't understand the difference between IOSTANDARDs, they all seem to give same logic 1 value. 

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Xilinx Employee
Xilinx Employee
16,101 Views
Registered: ‎02-02-2010

You can use the TI Digital Power Designer software to change the VCC levels on the board but caveat emptor, there may be some board components that will not function if you change the VCC.


@praveendath92 wrote:

I just had a check. The card seem to support only 2.5V logic 1 :( 

Is there a way I can configure the board with VCC 1.2V. I don't understand the difference between IOSTANDARDs, they all seem to give same logic 1 value. 


 

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Historian
Historian
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Registered: ‎02-25-2008


@praveendath92 wrote:

I just had a check. The card seem to support only 2.5V logic 1 :( 

Is there a way I can configure the board with VCC 1.2V. I don't understand the difference between IOSTANDARDs, they all seem to give same logic 1 value. 


Basically, IOSTANDARD tells the tools what supply voltage is connected to the bank in question. (There is more to it but that's the gist.) Setting IOSTANDARD to LVCMOS12 when the supply voltage is 2.5V doesn't magically make the pin's output range swing to 1.2V. 

 

You MUST use the proper supply voltage. 

----------------------------Yes, I do this for a living.
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Registered: ‎06-04-2013

Excuse me if I'm wrong here, Aas ML605 supports IOSTANDARD LVCMOS12 I'm supposing there would be an esy way to set VCC as 1.2V, may be repositioning jumpers or connecting 1.2V from an external power to some pins.

 

I tried using the software amandaw suggested. It wasn't so easy. I know, it's stupid of me to expect everything to happen just like that but atleast in this case I'm guessing there is a easy way to meet my requirement. 

 

Any ideas ? 

 

Just to make it clear, my requirement is 1.2V for logic 1 at atleast 15 pins of ML605.

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Xilinx Employee
Xilinx Employee
16,083 Views
Registered: ‎02-02-2010

You could try using a level shifter.

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Historian
Historian
16,079 Views
Registered: ‎02-25-2008


@praveendath92 wrote:

Excuse me if I'm wrong here, Aas ML605 supports IOSTANDARD LVCMOS12 I'm supposing there would be an esy way to set VCC as 1.2V, may be repositioning jumpers or connecting 1.2V from an external power to some pins.


 Remember that the FPGA chip itself suppots 1.2V I/O. Does the board support it? I don't know. I don't have the time to read through the user guide for a board I don't have, but I suggest that you do so. It may well be that the FMC board cannot do 1.2V. 

 

The design of an evaluation board is based on what the vendor thinks will be the most useful to the most people. If it turns out that most people -- especially those who need an eval kit -- don't need 1.2V I/O then they will not provide that supply. Simple as that. 


Just to make it clear, my requirement is 1.2V for logic 1 at atleast 15 pins of ML605.


The level shifter might actually be the way to go. Or you could spin your own board.

----------------------------Yes, I do this for a living.
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