SMARC IMX95 Buttonless Power Sequencing

Technical Support
1

From SMARC 2.2:

image
image1185×383 158 KB

Am I able to configure the SMARC IMX95 to automatically boot on cold power on? I do not want to have any buttons on my custom carrier board.

2

Hi, I’m the Toradex AI Assistant.

I might make mistakes or occasionally get you wrong. Our support team will step in if needed.

To provide the most accurate guidance for your SMARC iMX95 configuration, could you specify which OS and version you’re running? You can use the tdx-info command to get detailed information about your setup - more details are available at: Getting Device Information with Tdx-Info | Toradex Developer Center

SMARC Power-Up Behavior Overview

Based on the SMARC specification, there are multiple power-up scenarios available for SMARC modules. The ability to automatically boot without a power button depends on the specific module implementation and configuration.

Power-Up Scenarios

According to the SMARC specification, there are four different power-up sequence scenarios:

  1. Power up sequence scenario 1: With sleep power domain and power button
  2. Power up sequence scenario 2: With sleep power domain, no power button required
  3. Power up sequence scenario 3: Without sleep power domain, with power button
  4. Power up sequence scenario 4: Without sleep power domain, no power button required

Automatic Boot Configuration

For your requirement of automatic boot without buttons, you would need either scenario 2 or scenario 4, both of which support automatic boot without requiring a power button press.

The key considerations are:

  • Module Design Dependency: The power button behavior depends on the specific module design and configuration
  • Carrier Board Design: You can design your custom carrier board without implementing the POWER_BTN# signal connection
  • Power Sequencing: The module will assert CARRIER_PWR_ON when ready, which your carrier board should use to enable power rails

Next Steps

Once you provide your OS version information, I can give you more specific guidance on:

  • How to configure your particular setup for automatic boot
  • Any device tree or bootloader configurations needed
  • Carrier board design considerations for your SMARC iMX95

Best regards, Toradex AI Assistant.

Did you like my answer? :+1: :-1:

If I answered your question, please tick the “Solution” checkbox.

For follow-up questions to me, please use @ToradexAI in your post.

3

The Power_BTN# signal on the Toradex SMARC iMX95 module is directly connected to the ONOFF input of the iMX95 SoC. The transition from the Off state to the On state is managed by the SoC’s BBNSM module:

image
image971×162 12.4 KB

This means that if your board design does not include a physical power button, you will need to implement circuitry to automatically trigger the ONOFF signal (simulating a button press) when the main power rail is applied.