NEC MPI4E Raspberry Pi Compute Module Setup Guide

Loading ...

This timer’s value should be set high enough to ensure that any software running on the

Compute Module will be able to send the periodic reset command to the display, even under

heavy load conditions.

The Python SDK includes support for sending the Watchdog Timer reset commands to the display, as

well as configuring the timer settings. See the example file reset_display_wdt.py included in the

SDK for more details. See Python Based NEC PD SDK on page 65.

See sections 6.12 on page 48 through 6.14 on page 49 for details on configuring the Watchdog Timer

settings via the OSD.

5.13 Controlling the Compute Module power

Power to the Compute Module can be set to turn on automatically when the display power is turned on,

manually via the OSD, or manually via a command to the display. See section 6.2 on page 44 for details.

When the display power is turned off, the Compute Module power can remain on, or automatically shut

down and turn off with the display. See section 6.5 on page 45 for details.

Important: To avoid possible file system corruption, it is highly recommended to use the Shutdown

Signal to gracefully shutdown the system. See section 5.10 on page 38 for details.

5.14 Controlling the cooling fan automatically based on the CPU

temperature

The display’s cooling fan is automatically turned on based on a temperature sensor located near the

Interface Board. However, if desired, it can also be directly controlled based on the actual Compute

Module’s internal CPU temperature.

Use the Raspberry Pi Configuration tool available from the system menu and select the “Performance”

tab. Enable the fan setting, change the Fan GPIO to 24, and enter the desired temperature for the fan to

start operating. Note that a reboot will be required for the settings to be enabled.

Alternately, the settings can be made directly to the “config.txt” file by adding a line such as the following

example:

dtoverlay=gpio-fan,gpiopin=24,temp=70000

This sets the threshold temperature to 70°C and uses GPIO 24 to signal the fan.

See the following information for configuring the various boot overlay options:

https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README

Loading ...

NEC MPI4E RaspberryPi 4 System on a Chip Solution