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Bit of IQ

The '7007s is actually the same die as the (nominally larger) '7010. They use fuses to disable one of the ARM cores, and it's only possible to access about 70% of the FPGA fabric. This limitation is actually enforced by the development software; the chip has 100% of the FPGA fabric present (and tested). The FPGA bitstream header contains an identifying code though, which stops you from building a binary for the '7010 and loading it into the '7007s. The upside is that you can fully utilise "100%" of the '7007s fabric without running into problems (as "100%" is really only about 70% of the fabric, which is a fairly modest utilisation).

Other Xilinx Zynq-7 chips nobbled this way: '7020 => '7014S '7015 => '7012S

More recent families (e.g. Ultrascale Plus) do a similar thing, e.g. XCVU5P and XCVU7P have the same pair of dies but very different prices.

Regards, Allan

Reply to
Allan Herriman
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It is nice to be able to drop the bigger part onto the PC board, even if we have to pay more.

One 700 MHz ARM core is usually overkill, especially with an FPGA attached.

We have used some Altera chips with different specified numbers of CLBs and different prices that turn out to be identical; either runs the bit stream compiled for the other. Ditto speed and temperature grades, apparently.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

Of course that might not continue to be the case, especially if there's some yield problem in future--the mfr is within its rights to exceed specs if it likes. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

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a place I worked eons ago used a cheaper reduced memory version of a DSP, someone had made a mistake in a linker file so few bytes of the memory that wasn't supposed to be there was used, it worked just fine because it was th e same die as the bigger chip. Until, the volume got so high the manufactur e made a new die that actually had less memory and the production ground to h alt with everything failing and much panic

Reply to
Lasse Langwadt Christensen

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