I'm working on a raspberry pi tablet. It has a CM4 a custom breakout board and an LCD panel (haven't tested touch yet).
Datasheet of the LCD panel I'm currently using: https://drive.google.com/file/d/1bYvQ10 ... drive_link
The exact Panel I'm using can and probably will change but the resolution and refresh rate should stay the same.
To my knowledge there are 2 ways to connect a CM4 to an LCD panel:
I can think of at least two more:
- SPI (may be too slow)
- DPI (uses all of the GPIO)
1. Convert the HDMI to MIPI signals using a PCB that the supplier provides. The problem is that to make the device more cost effective i would need the source code of the PCB so that I can integrate it into my main PCB but it's closed source and only after a certain minimum order quantity do you get it which is currently too high for me.
2. Use the MIPI DSI connector of the MC4. But this requires drivers and if the user has to install the drivers themself, it's not that good. Also I'm not sure how difficult it is to write the drivers needed. Also the Official touch screen uses no drivers that you need to separately install and it uses the onboard DSI. How does that work?
Drivers are built in to RPiOS.
Option 1 seems easier to me but that way i would have 2 PCBs in the tablet (HDMI TO MIPI PCB, CM4 breakout PCB) in the first few units before I get the source code. Option 2 seems more difficult but would also be more cost effective.
Hmm, commercial product? Intending to sell this as a finished product? Best advice I can give is that you find a local expert and pay them for their skills and experience. Though I guess you could contact the screen vendor and see if they'll release the PCB design/schematic under NDA.
Statistics: Posted by thagrol — Fri Mar 15, 2024 1:00 am