THERM_MAXTEMP_OUTRANGE_ALERT is used at the device level in order to generate device warm reset. The alert is ring when the device overheats and exceeds the maximum temperature limit specified for the device, namely 125°C.
The following is the sequence to ring the THERM_MAXTEMP_OUTRANGE_ALERT:
- For the output to go active (‘1’), the VTM has to be configured to operate with at least one of its temperature sensors enabled, and WKUP_VTM_TMPSENS_CTRL_j[11] MAXT_OUTRG_EN = 1 for the corresponding enabled sensor.
- In addition, WKUP_VTM_MISC_CTRL[0] ANYMAXT_OUTRG_ALERT_EN has to be set to ‘1’.
- With the previous configuration set and at least one of the temperature sensors properly configured, and enabled, if the temperature of the die ever exceeds the programmed value in WKUP_VTM_MISC_CTRL2, the VTM output will be driven ‘1’ once the sensor detects the programmed maximum temperature.
- At the device level the VTM output, THERM_MAXTEMP_OUTRANGE_ALERT, will drive the PLL controllers into warm reset state with the PLL controllers entering CHIP_0_RST condition, at the same time that all the PLLs go into clock bypass mode.
- By the actions described in No.4, the device will considerably reduce its power consumption, which over the passing of a few seconds will cause the device to reduce its temperature.
- The VTM sensor continues to read the temperature and once the code corresponding to the programmed value in WKUP_VTM_MISC_CTRL2[25-16] MAXT_OUTRG_ALERT_THR0 is detected the VTM drives THERM_MAXTEMP_OUTRANGE_ALERT = 0.
- After No.6 is fulfilled, the PLL controllers no longer have the THERM_MAXTEMP_OUTRANGE_ALERT driving the CHIP_0_RST request and thus the PLL controllers bring the SoC out of reset and the boot sequence re-starts. At the same time the PLLs get out of bypass mode and start with their target programmed frequencies for the boot process.
Note: THERM_MAXTEMP_OUTRANGE_ALERT output of VTM is mapped to WKUP_VTM_MISC_CTRL[0] ANY_MAXT_OUTRG_ALERT_EN.
Notice that exceeding of the programmed value in WKUP_VTM_MISC_CTRL2[9-0] MAXT_OUTRG_ALERT_THR boundary doesn’t result in a PORz (cold reset) event, but instead a CHIP_0_RST event. Otherwise if cold reset is applied to the MCU/WKUP domains of the device, the VTM will be fully reset and the output THERM_MAXTEMP_OUTRANGE_ALERT will be cleared to ‘0’ immediately.