2021-02-12 08:42 AM
Hi, is there a way to get the B-LCDAD-HDMI adapter to work together with TouchGFX? So far I could only get it to work in i few CubeF7 examples, but those do not involve TouchGFX, CubeMX and so on...
Setup: STM32F769I-Disco + BlLCDAD-HDMI + Waveshare 7"
The examples provided by CubeF7 are also not running perfectly since the Screen is flickerung and the Image is shown two times (one is moved about 1/4 inch towards the Bottom.) Is there a way to adress those two issues?
2021-02-15 06:42 AM
Thank you! Now it works with the desired frequency.
Can you tell me how I can calculate those numbers?
Earlier I used a timings calculator (https://tomverbeure.github.io/video_timings_calculator) to get the Numbers in "HDMI_Format[]"
But I don´t know how I can come up with the Numbers in "HDMI_PLLConfig[]"
And there is one more issue. Connected to my projector or computer-Monitor, everything seems to be fine. But at the waveshare display, there is a shaddow a few mm under the real image. It is also there in your 1024x600 example. There is also a burn-in towards the edge that disappears after a few minutes when it´s unplugged (this does not appear when I connect the Display to my computer) I have ordered a new display to be shure it is not a problem of the Unit.
However I noticed that this shaddow comes further down, when I change the Numbers in "HDMI_Format[]" to
{1024, 104, 176, 72, 600, 10, 33, 3, HDMI_ASPECT_RATIO_16_9, LCD_DSI_PIXEL_DATA_FMT_RBG888}
Those Numbers were calculated by the Timings calculator for 120Hz. I tested it just out of curiosity. Every other Setting stayed the same.Thank You!
2021-02-15 08:30 AM
The line timings are based on ones I found in a 1024x600 panel manual, seemed to be some flexibility in those. I didn't find a good reference, so I used ones that worked on my multisync UHD monitor. You could use your own numbers, or dig up the manual for the panel WaveShare is using.
The PLL timings I did with a pencil and paper based on my understanding of how raster displays work, and the limitations of the DSI and STM32 design to hit certain numbers. Tends to flow through the pixel clock, and the rated capacity of the DSI in 2-lane configuration. I can mechanically generate timing tables. The DSI clock needs to meet or exceed the pixel data rate, and not exceed 500 MHz. The 2-lanes is limiting. I think 1366x768 is about the limit of the STM32 implementation.
Monitors tend to want things hitting close to 50 or 60 Hz frame rates, whereas LCD panels of fixed geometry, are concerned primarily with pixel clock frequency range.
Dark corners are more of a back-light issue.