ZYNQ temperature

Well, all chips have a high temperature shutdown, but you mean one that was designed in, right?

-- glen

Yeah, something it might recover from. As it seems to do.

I did find this:

ds190-Zynq-7000-Overview.pdf

an automatic power-down."

I wonder what we specified!

There are references in ug585 (the Zynq TRM) to ug480 for the temperature sensor stuff, it looks to be common to all the 7 series.

We epoxied a pin-fin heat sink to the top, and added a fan. That helps a lot.

Den mandag den 11. maj 2015 kl. 19.59.43 UTC+2 skrev John Larkin:

looks like you have to enable it (it may be default) and you have to load t he PL

of the OT Upper Alarm register (listed in UG480) have not been configured. When the die temperatu re exceeds the threshold set in the XADC's Control register, the ov er-temperature alarm ( OT) becomes active. The OT signal resets when the die temperature has fallen below set threshold. The OT alarm can also be used to automatically power down the PL upon activ ation. The OT alarm can be disabled by writing a 1 to the OT bit in the XADC's Configuration regi ster. Note: these registers are in the XADC and are accessible using the DRP.

-Lasse

Without me digging into the data sheet myself, can you tell me what the PL and PS are?

Programmable Logic (FPGA side of things) and Processor System (hard ARM processor and some peripherals).

It's probably shutting down at 125C, without our specifically programming any temperature.

Extensive searching, by us and by Avnet, finds no fan that matches the hole spacing on the MicroZed board. So we'll fab a little aluminum adapter plate and use a standard fan. With a pin-fin heat sink glued to the 7020 FPGA, and the fan blowing down on that, we can run at 100C ambient.

Reminds me of an array processor I worked on in the early 80's. It had ECL gate arrays in ceramic PGA packages with a heat sink on each chip and a specially designed plenum which slid over each one to direct air across the heat sink. This machine was as fast as a CRAY-1 and only a few years later.

d the PL

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The MicroZed has a -I part on it, right? Those parts are spec'd at a max j unction temp of 100 C. You need the Expanded temperature grade parts (Q) t o get the 125 C junction temps.

It's 99% likely that all the chips come off the same wafer. The faster ones may get binned as the high-temp versions.

The real issue is timing margins, and our fastest clock is only 128 MHz.

(We buy two different Altera parts, one with twice the logic cells and RAM and price and stuff. They are actually identical, run the same bitstreams compiled for either part.)

Here's the fan, with its adapter plate. The box runs fine at 100C ambient. Next time we recompile the design, in a couple of months maybe, we'll bring out the chip temperature sensor to see how hot it actually is inside there.

It's really insane that we should have to do this.

I once built and calibrated a ring oscillator to measure FPGA chip temperature. That's another story.

Den onsdag den 13. maj 2015 kl. 22.18.29 UTC+2 skrev John Larkin:

load the PL

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nabled via the bitstream and the

es inactive or a

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ntents of the OT Upper Alarm

perature exceeds the

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activation. The OT alarm can

n register.

P.

x junction temp of 100 C. You need the Expanded temperature grade parts (Q ) to get the 125 C junction temps.

if you have a jtag cable you should able to read it out

and I think the driver is installed by default in the xilinx linux image some where down in /sys/bus/iio/devices/iio:device0

-Lasse

MicroZed can be purchased off the shelf with either a -C or -I. A -Q is possible through a custom build by contacting customize at avnet dot com

Bryan

We are buying AES-Z7MB-7Z020-SOM-G. I'm not sure which version of the FPGA is on that.

Seems fine at 100C ambient, with our fan. I couldn't persuade the engineer to crank the temperature any higher. I like to test things to destruction.

Nobody at Avnet wants to discuss the fan-mount hole spacing, or name a fan that fits.

I don't have the measurements, but it seems like it's a very common cooler among motherboards:

Regards Tomas D.

Here it is:

Maybe fits the size?

Regards Tomas D.

Den torsdag den 14. maj 2015 kl. 23.53.37 UTC+2 skrev Tomas D.:

not even close

the mounting fan holes on the Microzed is 2mm, and the diagonal spacing is ~31.5mm, that is some where between a 25x25mm and 30x30mm fan

and the heatsink has to fit in a ~17x17mm footprint because there are caps that are taller than the Zynq right next to it

-Lasse

The hole spacing may be English units, namely 1.25"

I did look at a lot of CPU cooler fans. There are many, many hole spacings, except that one.

We'll just order a bucket of those adapter plates and get on with our lives.

We're gluing a Cool Innovations pin-fin sink to the top of the FPGA and blowing air down on that.

Without the forced air, the pin fins are useless. But the base of the heat sink spreads heat laterally out from the central hot-spot (a flat metal plate works the same) and cuts junction temp by 5C or so.