I have setup a design in the xczu19eg FPGA.

To implement Over temperature protection have used the System Management Wizard IP to enable OT and have configured the same for trigger and reset.

When the board reaches the Trigger temperature it shuts down it’s operation as intended. But when the temperature decreases it doesn’t show any indication of startup sequence being run, even after keeping it on for a very long time.

In the IP Core documentation they have mentioned contradicting statements as far as I see.

“when the die temperature exceeds the OT upper threshold (or the default of 125°C), the OT alarm logic output becomes active and 10ms later the device initiates a shutdown sequence. When the automatic shutdown starts, the device is disabled and GHIGH is asserted to prevent any contention (see the UltraScale Architecture Configuration User Guide (UG570) [Ref 4]. When OT is deasserted (50°C as shown in Figure 4-4), GHIGH is also deasserted and the start-up sequence is initiated releasing all global resources.” – This statement supports start-up.

also

“The automatic shutdown feature is intended to prevent permanent damage to the device. After the temperature has gone below the OT lower (57h) setting and OT is deasserted, the device should be reconfigured to ensure the device is reset to a known safe state.” – This statement tells us to reconfigure the FPGA after shutdown occurs.

I am confused by the same and was wondering if anyone here has experience in this feature of the IP Core.

Any help would be greatly appreciated.

Reference – https://0x04.net/~mwk/xidocs/ug/ug580-ultrascale-sysmon.pdf (page 91, 92, 93 & 94)

https://docs.amd.com/v/u/en-US/pg185-system-management-wiz

Does the IP actually allow this feature or restart after the temperature decreases, or should I enable something else in the design. I am asking this because to enable shutdown I had to configure the xdc file with –

“set_property BITSTREAM.CONFIG.OVERTEMPSHUTDOWN ENABLE [current_design]”

So do I have to do a similar thing for Reset of OT.

As temperature hits the upper limit of shutdown the board shuts down, but after the board cools down it doesn’t boot up by itself.
But when I cold/warm reboot the entire system, without having to flash the board with a fresh image it boots up and runs as if nothing happened.

Thank you.