Critique my first PCB

[carl0s]

Thanks for the pictures. I have a couple of the 480*480 HX8379-C coming to have a play with.
I think because they are GRAM-less, they are operated in Video mode, where hsync and vsync is sent along with raw pixel data, so no tearing effect line is used.
The 320*320 panel that I have been using (st7796) has a GRAM/framebuffer and works in adapted command mode.
Check ST application note AN4860.
This is the same as my 800*800 ILI9881C screen, which I have not used yet because it requires 3 lane MIPI.

[luiHS]

 
How are you doing with your tests with the round screens? I have already designed the PCBs to use the two 2.1 and 2.4 inch screens.

What I do notice when testing the 2.4 screen is that there is a certain Tearing effect, as if the TE signal was not being used, that makes when playing videos, when scenes with rapid changes come out, a certain cut is shown in the middle of the screen .

The 2.4 screen is much brighter than the 2.1 screen, and although it has less resolution, I think it looks better.

 





 

[carl0s]

Hey Lui

Great work. I can see the tearing too..
Is that stm32F769 with mjpeg video? I think it looks great.

I have done zero work really. I am still playing with SSD2828 bridge for the 4-lane display. No real reason other than to not give up. but it's just a part time hobby for me and I'm just too tired in the evenings lately to do anything

I agree the 320*320 Panasys screen is great and bright.
What about the 480*480 one with the 0.2mm pitch connector? I have a couple of those, but no breakouts for the connector yet and not bothered about having a PCB made just yet.

[carl0s]

Are you sending the TE enable DSI cmd? (DSI_SET_TEAR_ON)

I have found that I don't get any screen output without it.. not sure if I mentioned that on here previously.

[luiHS]

Hey Lui

Great work. I can see the tearing too..
Is that stm32F769 with mjpeg video? I think it looks great.

I have done zero work really. I am still playing with SSD2828 bridge for the 4-lane display. No real reason other than to not give up. but it's just a part time hobby for me and I'm just too tired in the evenings lately to do anything

I agree the 320*320 Panasys screen is great and bright.
What about the 480*480 one with the 0.2mm pitch connector? I have a couple of those, but no breakouts for the connector yet and not bothered about having a PCB made just yet.

Yes, my PCB boards are with the 769, in addition to an SDRAM, SD card holder and backlight voltage booster.

About the connectors, the 320*320 2.1-inch screen needs a 0.5 mm pitch connector, and the 480*480 2.4-inch screen needs a 0.3 mm pitch connector. Both connectors available in Mouser.

[luiHS]

Are you sending the TE enable DSI cmd? (DSI_SET_TEAR_ON)

I have found that I don't get any screen output without it.. not sure if I mentioned that on here previously.

I will check it, I do not remember now.

[carl0s]

Hey Lui

Great work. I can see the tearing too..
Is that stm32F769 with mjpeg video? I think it looks great.

I have done zero work really. I am still playing with SSD2828 bridge for the 4-lane display. No real reason other than to not give up. but it's just a part time hobby for me and I'm just too tired in the evenings lately to do anything

I agree the 320*320 Panasys screen is great and bright.
What about the 480*480 one with the 0.2mm pitch connector? I have a couple of those, but no breakouts for the connector yet and not bothered about having a PCB made just yet.

Yes, my PCB boards are with the 769, in addition to an SDRAM, SD card holder and backlight voltage booster.

About the connectors, the 320*320 2.1-inch screen needs a 0.5 mm pitch connector, and the 480*480 2.4-inch screen needs a 0.3 mm pitch connector. Both connectors available in Mouser.

Cool.
Yes I have the connectors.

[luiHS]

 
I receveid my new PCB for the 2.1 inches round screen. Ready to assemble and test.

Next week I will receive PCB for the 2.4 inches, I hope I can solve the TE problem, its a good round screen, good size and very bright, but the tearing effect spoils something when playing videos with fast movements.

[carl0s]

 In your video it is the 2.4" screen already. Ha, I wondered about that.. the connector is going under the piece of paper isn't it?

[luiHS]

In your video it is the 2.4" screen already. Ha, I wondered about that.. the connector is going under the piece of paper isn't it?

The first tests were with an HDMI controller board, to check the resolution and brightness of each screen.

Now I go with the PCBs that have all the electronics based on the 769, and connect with 3 wires, 2 wires for 5 volt power supply and a third wire for a serial port to control which videos are played.