Is there any way to disable JTAG for Sptantan3AN

NO

You cannot disable the JTAG !

and why do you want to remove the powerful JTAG link from your board application ? One Time Programmable = Not Upgradeable System !

Larry

ofcourse u can. just ground them!

snipped-for-privacy@am> > Hi,

that doesnt prevent the JTAG being used if the chip is desoldered... so it really isnt disabling the JTAG just making it harder to access

lso when the S3AN are to be programmed before sending to assembly fab?

Antti

I do agree that there are ways on board with which you can make it very difficult for other people to use JTAG. But I was wondering if there is any solution to make the FPGAs as OTP (One time Programmable). I think for Spartan XL FPGAs we used to get OTP Proms. So was wondering if there is any similar solution for Spartan3AN.

-- Goli

the internal FLASH of S3AN does have OTP write protect fuse. so if you set that protection then the S3AN internal memory comes read only but it will not prevent configuration by other means

Antti

rd

Hi,

If design security is an issue consider Actel iso. Xilinx Spartan or other Xilinx devices with AES protection ....

Bert.

Bert,

1) Design change from Xilinx to Actel may cause many man-months of struggle. 2) Field updates of Actel FPGA are only secure for non M7/M1 devices. Any design that updates on field Actel M7/M1 silicon has design theft security equal to NIL VOID ZERO 3) Lattice ECP2 have non-volatile AES key, making them best candidate if design security/theft is of concern, also the design migration from Xilinx to Lattice is much much more easier then Xilinx to Actel

Antti

If it's non-volatile, is it not "relatively easy" to extract the key from the chip by invasive methods? I say "relatively", compared to the volatile keys in a virtex device - still not a trivial task :-)

Cheers, Martin

--
martin.j.thompson@trw.com 
TRW Conekt - Consultancy in Engineering, Knowledge and Technology
http://www.conekt.net/electronics.html

Technology

I don't think design security is the issue if the OP's original system had an external PROM, whether or not it was re-programmable. Preventing inadvertent re-programming can be accomplished at the board level as noted, but if the device is delivered as a chip it is not as simple. I've seen microcontrollers programmed and sold as application-specific parts. Often the data sheet for the programmed part does not make it clear where the part came from, and the chip is re-marked. In this sort of scheme, you could always call out the JTAG pins as grounds...

What is the actual application?

Regards, Gabor