Yeah, the resistors, I remembered that I red about it somewhere some time ago so I tried to short-circuit them yesterday and I managed to run the sketch at SD card SPI clock divider set to 2 (TFT SPI clock divider set to 2 as well). That decreased the time to load and show an image to about 130ms (vs 190ms when SD SPI clock divider is set to 4 and TFT SPI clock divider set to 2). But at that speed I was getting artifacts, like some of the pixels (even whole lines) were of wrong color. So I started to mess around with the breadboard and connections and instead of improving the situation I made it worse and ended up with ‘File open failed’ errors and could not make it work again. So I reverted back to SD card SPI clock divider of 4 and TFT SPI clock divider of 2 which is stable (that’s the settings I used for the video).
Can you send me a link to that 3.5" TFT, the ones I found seem to have a parallel interface and not a serial one (or maybe they have both?).
Btw. all the videos work fine for me, try again or try my github page.
On the Due, the system clock can be divided by values from 1 to 255. The default value is 21, which sets the clock to 4 MHz like other Arduino boards.
So with the above 21 x 4 = 84Mhz Clock.
If you are using DIV2 you are effectively driving the SD/TFT at 42MHz.
Sure I can: This is the display. I have the 8bit version from the same seller, but could order the SPI as well (or find a way to re-wire mine in SPI mode)
The first link is working OK today, perhaps some issue with my ISP yesterday.
DMA kicks ass! The rest is useless, I can get my UNO to run faster, using direct port manipulation with an 8 bit display.