We have mounted RPi CM4 on our newly assembled application board having HDMI and RJ45 connectors. There is no display when the HDMI cable is attached to the screen. The LED ACT is flashing green and the the LED PWR is stable turned on. The connections between the HDMI connector and the CM4 RPi has been done the same way as mentioned in KiCad project of CM4 IO board. The main power supply to the application board +5 V is stable. The HDMI power switch RT9742SNGV is working and gives +5 V out for the HDMI connector.
We also have CM4 IO board as reference. We already have programmed the RPI OS on the eMMC of CM4 using CM4 IO Board. The CM4 gives display on the CM4 IO board. The LED ACT D2 is flashing green and the LED PWR D1 is stable turned on.
Any idea what could be the issue ? Kindly let us know if there are debug signals that we can check with digital multi-meter.
We also have CM4 IO board as reference. We already have programmed the RPI OS on the eMMC of CM4 using CM4 IO Board. The CM4 gives display on the CM4 IO board. The LED ACT D2 is flashing green and the LED PWR D1 is stable turned on.
Any idea what could be the issue ? Kindly let us know if there are debug signals that we can check with digital multi-meter.
Statistics: Posted by TommyBills — Tue Jan 20, 2026 4:07 pm — Replies 1 — Views 31