Fan

The phyCORE-AM62x development kit provides fan connectivity via a 4-pin Hirose connector at X16 (VCC_5V0_SW rail). The fan is intended to be mounted directly to the processor heat sink for thermal management. The regulated 5V output is enabled by driving a GPIO0 low (0), turning the fan on. When the GPIO0 is pulled high (1), the 5V supplied to the fan connector will be turned off. This guide will demonstrate how to test your connections to the header x16. To learn more information about the phyCORE-AM62x thermal management and fan utilization, please see section 4.9 in the Hardware Manual .

phyCORE-AM62x 1576.1 Fan

Requirements

The phyCORE-AM62x development kit does not include a heat sink and fan. The below are the two fans that were tested on the PHYTEC hardware:

Item

Description

Link

Heat Sink

(29mmx29mmx9.5mm)

Digikey link (heat sink)

Fan

DC axial fan, 30mm square x 10mm

Digikey link (fan)

Female Connector

PCB 1576.1 version 4xpin keyed header

Digikey link (female connector for 1576.1)

Female Connector

PCB 1576.2 version 4xpin keyed header

Digikey link (female connector for 1576.2)

Crimping Terminals

4x crimping jackets

Mouser link
phyCORE-AM62x Fan Schematic

Hardware Setup

  • Connect fan to the 4-pin Hirose connector located at X16.

    Warning

    Please note that the PCB version 1576.1 has a different connector and pin 1 placement than the newer PCB 1576.2 version.

1576.1

1576.2
../_images/pb-07124_fan-closeup-pin1.png ../_images/pb-07124_fan-2.png

Enabling the Overlay

  • Power on the development kit and stop in U-boot.

  • Load the device tree overlay required for exporting the GPIO signal that controls the fan and then boot the board.

    Target (U-boot)
    setenv overlays k3-am62-phyboard-lyra-gpio-fan.dtbo
boot

Note

For more information about overlays see chapter Configuring the Bootloader.

  • Verify that the “gpio-fan” was exported properly to gpio-460.

    Target (Linux)
    cat /sys/kernel/debug/gpio
    Expected Output
    root@phyboard-lyra-am62xx-2:~# cat /sys/kernel/debug/gpio
gpiochip2: GPIOs 360-367, parent: i2c/1-0021, pcf8574, can sleep:
gpio-360 (GPIO0_HDMI_RST      |reset               ) out hi ACTIVE LOW
gpio-361 (GPIO1_CAN0_nEN      |standby             ) out lo
gpio-362 (GPIO2_LED2          |led-2               ) out lo
gpio-363 (GPIO3_LVDS_GPIO     )
gpio-364 (GPIO4_BUT2          |menu                ) in  lo IRQ
gpio-365 (GPIO5_LVDS_BKLT_EN  )
gpio-366 (GPIO6_ETH1_USER_RESE)
gpio-367 (GPIO7_AUDIO_USER_RES)

gpiochip1: GPIOs 368-419, parent: platform/601000.gpio, 601000.gpio:
gpio-391 (                    |home                ) in  lo

gpiochip0: GPIOs 420-511, parent: platform/600000.gpio, 600000.gpio:
gpio-433 (                    |green:heartbeat     ) out lo
gpio-452 (                    |led-1               ) out lo
gpio-460 (                    |gpio-fan            ) out lo ACTIVE LOW

Toggling the Fan

  • Turn the fan ON.

    Target (Linux)
    echo 1 > /sys/class/thermal/cooling_device0/cur_state

Note

Run the command above 3-4 times to have the fan stay ON consistently.

  • Turn the fan OFF.

    Target (Linux)
    echo 0 > /sys/class/thermal/cooling_device0/cur_state