LCD Cape Interface with MTK
Added by Lucas Uecker over 2 years ago
Hello-
I'm putting together a PCB to connect the AM3352 SOM board to an LCD touchscreen. As a quick prototype I've plugged the MTK into a Newhaven Display cape ( https://newhavendisplay.com/content/specs/NHD-7.0CTP-CAPE-L.pdf ) and got no video output. I know the MTK has a few busses swapped from the Beaglebone Black, but the DVI pins are the same as far as I know. I've tried uncommenting some of the lines in /boot/uEnv.txt referring to HDMI output... but no change. Hopefully this is a obvious-in-retrospect thing.
Thanks!
Replies (3)
RE: LCD Cape Interface with MTK - Added by Jonathan Cormier over 2 years ago
Hi Lucas, what kernel version are you running? Can you also attach a full bootlog?
RE: LCD Cape Interface with MTK - Added by Lucas Uecker over 2 years ago
I've attached the output of the debug serial. The MTK is largely fresh out of the box with the CL SD card. It says Linux version 4.4.30-ti-r64
| 9-1-22-CLout.txt (27 KB) 9-1-22-CLout.txt |
RE: LCD Cape Interface with MTK - Added by Jonathan Cormier over 2 years ago
Ahh okay. You can try to following instructions to switch to the -overlay version of the dtb and see if the cape manager auto detects the cape.
https://support.criticallink.com/redmine/projects/mitysom-335x_maker/wiki/Using_Debian_Community_Filesystem#Using-a-BB-BONE-LCD7-01-00A3dts-compatible-cape
Note: We generally don't use the beaglebone overlay system or the debian root filesystem so I'm not super familiar with it. Most of our custom baseboard designs, the device trees are set up statically and the filesystems are built using yocto. We can help with this if you need it.
I'm putting together a PCB to connect the AM3352 SOM board to an LCD touchscreen.
We've done a lot of LCD connected baseboards so I'd recommend emailing your PCB and Schematic design to use for review before building your first boards. Feel free to email them to support@criticallink.com. Let me know if you did so and I'll make sure someone looks at it.
I've tried uncommenting some of the lines in /boot/uEnv.txt referring to HDMI output
Note to get an LCD working, the HDMI settings are not sufficient as every LCD has its own very specific RGB LCD timings. Also, there is often a backlight that needs to be driven as well as a touchscreen driver. And a few support gpios.
