OVERTEMP_N signal driven low

We have a Xavier AGX module on a custom carrier board. It appears the OVERTEMP_N signal is being driven low as an output from the AGX module. We do not have a fan on the unit as it is passively cooled with a heat sink, but the unit is certainly not over temperature.

What could cause the OVERTEMP_N output to be driven low? Are there any other dependencies on this output signal besides the current temperature?

The same AGX module mounted on a dev kit carrier board has no problems powering up, but it does not power up on our custom carrier (using the same schematic as the dev kit carrier board) due to the OVERTEMP_N signal being driven low. When we bypass this output on our custom carrier, all is good.

hello andrew.mank,

you may also examine reported statistics by tegrastats utility, please refer to Thermal Specifications for the thermal trip points.

Thanks @JerryChang, but we are nowhere near the thermal trip point. The OVERTEMP_N signal is driven low on startup, which forces a power down. Is there something beside the thermal trip point which could cause that behavior?

hello andrew.mank,

it’s OVERTEMP_N / SOC_GPIO55 / GPIO3_PN.02 according to pinmux spreadsheets.
please check the cfg file, you may share the pinmux configuration file for the pin definition for reference,
for example,

pinmux.0x02440028 = 0x00000058; # soc_gpio55_pn2: rsvd0, pull-up, tristate-enable, input-enable, lpdr-disable

could you please setup serial console to gather bootloader messages for more clues.