BT818 PCLK settings

[Spyy]

Hi Rudolph,
thanks for your reply.

I have only one slave device connected on SPI bus, the Rivendi TFT without shift levels, because teensy 4.0 works already at 3V3.
I don't use resistors but direct connections. Correct?

With teensy 4.0 board, I init the EVE3/EVE4 with spi bus speed at 12MHz, after it works at 30MHz (with VM816C board works very fine).

After I bit of work on my library, I have resolved some issues with EVE4 chips.

cmd_testcard() works fine now. widgets and primitives too.

Now my problem is with assets stored on flash ram. Expecially with animation frame cmd_animframe().

The assets (images all ASTC 4x4 and animations all ASTC 4x4) on VM816 board work perfectly, but the same assets with BT817 don't work correctly.

I have noticed that with big size images (approximately more then 700x250) and with big size animation (approximately 800x250 for example), the BT817 show white screen or 3 half images of the same frame for example.

I don't understand where the problem is.
The flash state is correctly set in full mode.

What can I try to do?

For last, I have modified your library to work with Arduino IDE and it reports the same issues.

Concerning SPI speeds...i do the initialisation of the eve chip with 4 Mhz no dma spi and then throttle up to 25Mhz and do the dma spi bursts, which now works fine. Had problems with the intervallTimer of the teensy which was not working for me...it feels a bit of an interference of dma spi and the timer...perhaps interrupt issues. Now i do everything in the loop(), no timers or teensy threads. It is now doing the entire calculations for the display content including sending the display list via spi in approx. 0.1 ms...which seems to me very fast...

[Rudolph]

Hello,

On our development boards we utilize the Abracon LLC - "ABM8G-12.000MHZ-18-D2Y-T" 12Mhz 18pF crystal.

Best Regards,
BRT Community

Hi,

Ok...with this crystal, do i additional external capacitors?

Yes, 2x 33pF should work.

[BRT Community]

Hello,

Yes the manufacture recommends loading capacitors, we utilize 2x 18pF capacitors in our designs.

Best Regards,
BRT Community