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2026-09-06T06:03:57Z

Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex

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'''Documentation notice:''' This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

== Summary ==
The Waveshare CM4-DISP-BASE-5A is a compact I/O base board for the Raspberry Pi Compute Module 4 (CM4/CM4L). It integrates a 5-inch touch screen, four USB 2.0 ports, Gigabit Ethernet with PoE pins, and an HDMI output with 4K capability.

== Related products at JW Tech ==
* [https://shop.jw-tech.eu/p/WSAL22024 WSAL22024 – 5″ Touch Screen Expansion for Raspberry Pi CM4, PoE Header, Gigabit Ethernet, 4K Output]

== Technical overview ==
* The board supports all versions of the Compute Module 4 via a dedicated CM4 connector.
* It provides four USB 2.0 ports; on the CM4 these are disabled by default and require kernel configuration via config.txt.
* The HDMI port supports 4K@30fps output.
* Gigabit Ethernet with an RJ45 connector supports 10/100/1000 Mbit/s.
* PoE is provided via dedicated pins; actual PoE functionality requires an additional PoE HAT module.
* An RTC chip (PCF85063a) sits on the I2C-10 bus at address 0x51; a fan controller (EMC2301) sits at address 0x2f.
* A BOOT switch selects between USB boot (ON) and eMMC/MicroSD boot (OFF).
* The board features an M.2 port for NVMe SSDs or PCIe M-Key communication modules.
* Two switches control disabling of Wi-Fi (WF-DIS), Bluetooth (BT-DIS), and boot firmware write protection (WP-DIS).
* The display requires a driver to be installed; configuration is done via dtoverlay=vc4-kms-dsi-7inch in config.txt.

'''Commands and examples – verify before use:'''
<syntaxhighlight lang="text">
dtoverlay=dwc2,dr_mode=host
dtoverlay=vc4-kms-dsi-7inch
sudo reboot
libcamera-hello -t 0
libcamera-hello --list-cameras
libcamera-jpeg -o test.jpg
sudo hwclock -w
sudo hwclock -s
sudo hwclock --set --date="9/8/2021 16:45:05"
sudo hwclock -r
sudo hwclock --verbose
dtoverlay=i2c-rtc,pcf85063a,i2c_csi_dsi
dtparam=i2c_vc=on
dtoverlay=cm4io-fan,minrpm=500,maxrpm=5000,midtemp=45000,midtemp_hyst=2000,maxtemp=50000,maxtemp_hyst=2000
</syntaxhighlight>

== Notes and version constraints ==
* Do not plug or unplug any device other than USB and HDMI while the baseboard is powered on.
* Ensure at least 5 V / 2.5 A power supply is available for the CM4 before powering on; otherwise automatic shutdown or clock throttling may occur.
* The USB slave port is only for flashing images and cannot be used as an OTG interface.
* Connect the fan before powering on the baseboard; plugging it in after power-on can damage the control chip.
* When using the RTC, DSI and CSI must remain disabled.
* Camera and display configuration is version-specific (Buster vs. Bullseye/Bookworm); older systems may require extra steps such as raspi-config.
* PoE functionality requires an external PoE HAT; without it the feature remains unused.
* The display needs an additional driver; without it the screen will not work.
* The listed commands assume specific OS versions; behavior may differ on other releases.
* Verify the fan's rated voltage matches the connected voltage before replacing a fan.

== Source and revision record ==
* [https://www.waveshare.com/wiki/CM4-DISP-BASE-5A CM4-DISP-BASE-5A - Waveshare Wiki]
* Source revision: 104274
* Captured: 2026-09-03T03:33:31+00:00
* SHA-256: <code>04e7db8cbf1c7f28e38be49558edf8814353c19f6dba00574e72b1e5483d3dd0</code>

WSAL22024 – CM4-DISP-BASE-5A/en - Versionsgeschichte

JWTechPublisher: Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex