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Designing problem in FPGA

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Navya

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How DCI pins function? When it can be used as user I/O? and HOw?

Can we give same voltage for all banks power supply pins?

Please reply urgently
 

There are several types of the electrical standards which you can choose for pins in Xlinx FPGA's. Someof them requires special I/O voltages. If you do not connect proper I/O and reference voltages required for the specified type of pin it will be still working but do not meet proper specification (no guarantee that it will well work with external devices, voltage levels and other params will be outside specification requirements)

Can we give same voltage for all banks power supply pins
Click to expand...
yes,

bis
 

Its a vague answer. Can anyone please explain more about DCI pins?can i use them as user I/O pins?i want to interface spartan 3 fpga to platform flash PROM

Does each voltage pin needs a decoupling capacitor? Please guide with proper desigin.
 

well i don't know about DCI but regarding decoupling capacitor it is essential that you put a decoupling capacitor as close to the pin as possible for all Vcc pins.
 

In that document a atabular colum for virtex II device is given in page 12-12. Will the SSO limits be came for spartan 3 device too?
If not can you please tell?
 

Read a few times more this application note, you can find the following sentence:
The number of VCCO pins used by a device can be determined based on the Simultaneously Switching Output (SSO) restrictions given in the device documentation (data sheet and user guide).
Click to expand...
(page number 12 in version 2.1)
Open DS099.PDF after that, please. Find chapter "Simultaneously Switching Output Guidelines" and read them. If something is not clear, read again and again.

bis
 

I found in the document XAPP623.pdf that "capacitor range generally spans values from 0.001 µF to 4.7 µF. The exact value of these capacitors is not critical. What is critical is having some capacitor value in every order of magnitude over this range"

i found that the % used in bank 0 is 89% for our project. So can i put any capacitor?

Expecting your early reply
 

"Can we give same voltage for all banks power supply pins?"

well u need to provide VCCIO voltage for each bank depending upon the interfaces of external devices to that particilar bank.
Like, if u r interfacing bank1 of FPGA with any external device with its I/O voltage 1.8V, then u shud provide VCCIO1 with 1.8 volts.
 

    N

    Navya

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DCI pins are used if u don't want to use external resistor for impedance matching in stead use DCI option.
It shall be used for only output pins only and u have to use VRN and VRP pins to connect to external resistors.

For effective use IO in DCI mode also read the rules related to DCI that in a particular bank all VRN and VRP pins shall be connected and cannot be used as regular IO.

Read the voltage requirements for the particular IO type.
 

    N

    Navya

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