We use Toradex's Veridin i.MX8Mplus at our company.
At that time, the SOM_PW_ON signal is input to control the SoM's power supply. (Directly connected to the ON/OFF signal of the i.mx8MPlusSoC). *Please refer to the waveform on the attached oscilloscope.
Due to the circuit configuration on the SoM side, the voltage should be High (1.8V), but for about 800 msec after startup, it remains at an intermediate potential of approximately 0.3-0.4V.
I'd like to know how this voltage (0.3 to 0.4V) is handled as an ON/OFF signal on the SoC side.
This information was not included in the datasheet or reference manual.
I think that in cases of very short ON/OFF operations (<5s), the system may proceed to shutdown. Would the operation detection criteria be the transition from High to Low edge state and the duration of the Low state?
I would also like to know the exact minimum/maximum times for those times.
For i.MX8M Plus, ONOFF is handled as a level-held button input with configurable 0/50/100/500 ms qualification and 5/10/15 s forced-off timing, and your observed 0.3–0.4 V on a 1.8 V ONOFF net is most consistently interpreted as logic Low by the available input-threshold documentation.
Thank you for your reply.
The observed V values of 0.3–0.41.8V on the ONOFF network are most consistently interpreted as logically low by the available input threshold documentation.
By the way, could you also tell me about the voltage threshold that is interpreted as logically low?
Furthermore, if interpreted as logically low, the ON/OFF state will remain logically low for approximately 800 msec after startup before changing to logically high.
In that case, would it be considered that a button input occurred?
My concern is whether a button press might cause the system to automatically shut down immediately after startup.
I apologize. I would like to know the voltage threshold at which the logic value is interpreted.
Thank you for your reply.
The observed V values of 0.3–0.41.8V on the ONOFF network are most consistently interpreted as logically low by the available input threshold documentation.
By the way, could you also tell me about the voltage threshold that is interpreted as the logical high?
Furthermore, if interpreted as logically low, the ON/OFF state will remain logically low for approximately 800 msec after startup before changing to logically high.
In that case, would it be considered that a button input occurred?
My concern is whether a button press might cause the system to automatically shut down immediately after startup.
To the NXP TechSupport representative
What do you think about this matter?
I have one more question:
ON/OFF is processed as a level hold button input, with conditions of 0/50/100/500 ms.
Regarding that point, I believe the default is 0. In this case, if the level momentarily exceeds the logical high or logical low threshold due to noise or other factors, will the level be held?
I am concerned that with this default setting, if noise is received, there is a possibility of malfunction if something that causes a logic judgment opposite to the currently held level logic is introduced, even for a moment.
I have added a few more questions.
We apologize for the inconvenience, but please provide your response.