Verdin i.MX8MP ONOFF

Hi

I have a custom baseboard for the Verdin i.MX8MP and I’m trying to figure out the behaviour of the ONOFF signal.

The docs say that a press of any duration will turn it on, but a (configurable) long press will turn it off. When I press the power button, I find I need a longish (500ms+) to turn it on, but a very short press to turn it off.

Is this expected?
How can I configure the turn off time?

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Hello,

The behavior you’re observing with the ONOFF signal on your custom baseboard for the Verdin i.MX8MP module is influenced by the module’s power management configuration and the specific implementation on your baseboard. Typically, the ONOFF signal is indeed used to control the power state of the module, with a short press to turn it on and a longer press to initiate a shutdown or turn it off.

The discrepancy in the required press duration for turning the device on and off might be due to how the power management circuitry is implemented on your custom baseboard or the default settings configured in the module’s firmware or software.

To configure the turn-off time, you would typically need to adjust settings within the module’s software, specifically within the U-Boot or Linux kernel configuration, depending on where the power management control is implemented for your application. For the Verdin i.MX8MP, this configuration might involve modifying the behavior of the PMIC (Power Management Integrated Circuit) or adjusting the software debouncing settings related to the ONOFF signal.

  1. U-Boot Configuration: Check if there’s an environment variable or a configuration option in U-Boot that controls the ONOFF signal behavior. You might need to modify the U-Boot source code and recompile it if there’s no readily available configuration option.

  2. Linux Kernel Configuration: Within the Linux kernel, the behavior of the ONOFF signal can be managed by device tree settings or kernel module parameters related to the PMIC or GPIO handling. You would need to locate the relevant device tree file (.dts) for your module and custom baseboard and adjust the settings for the ONOFF signal handling. This might involve configuring the debounce time or specifying the behavior for different press durations.

  3. PMIC Configuration: If the ONOFF signal handling is managed directly by the PMIC, you might need to modify the PMIC settings through I2C commands or through a configuration interface provided by the Linux kernel (e.g., sysfs entries or a specific utility tool). This approach would require consulting the PMIC documentation for the specific registers or settings that control the ONOFF signal behavior.

Please note that making these adjustments requires a good understanding of the module’s hardware and software architecture, as well as the specifics of your custom baseboard design. Care should be taken to ensure that any changes do not affect the stability or functionality of the system.

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Toradex AI Assistant

Please, also check if these links can help you solve your problem:

Application Development - .NET Example | Toradex Developer Center.

Yes, if the Verdin i.MX8MP module is in the Off state, pulling the CTRL_PWR_BTN_MICO# line for any duration will immediately turn on the internal module’s power supply. However, this only works if the module already has a stable Vcc voltage provided on the related module’s pins. If your power button is also involved in powering on your custom carrier board’s power supply, it may be the reason for the observed behavior. Please double-check if your custom carrier board power supply is designed according to the recommendations listed in Chapter 3.1, Power Supply Design, of the Verdin Carrier Board Design Guide.

Thanks for this. We have a couple of other issues on the board and are working through those as some are power related.

I’ve just tried a Mallow board and it behaves the same as our board. A very short press of the power button will shut it down, and a longer press is required to wake it up.
Is that expected?