Purpose SD card and controller on TFT?

Other Hardware Displays
1

I have purchased an UNO, but know little about interfacing it.

From what I've read, a TFT display has both RAM and an SD card for graphics.

  1. Can someone clarify what the RAM holds vs the SD card? What limitations occur if the SD card is not used (not inserted)?

  2. Do all of them come with a controller on board that facilitates communication with an MCU? I assume it takes care of the parallel leads to the display itself, so that having the controller is big asset for the mcu?

  3. Is the communication between the mcu and the TFT module typically by SPI and I2C, or instead by 8 bit parallel to the controller?

2
  1. Can someone clarify what the RAM holds vs the SD card?

The TFT RAM holds the current screen image plus some sprites (small images that can be moved around on the screen). Since at those resolutions a single screen image would take up more RAM than the Arduino has and much of the FLASH memory it is good to have an SD card for mass storage if you want to have more than one image.

What limitations occur if the SD card is not used (not inserted)?

Your storage space will be very limited.

3

johnwasser:

  1. Can someone clarify what the RAM holds vs the SD card?

The TFT RAM holds the current screen image plus some sprites (small images that can be moved around on the screen). Since at those resolutions a single screen image would take up more RAM than the Arduino has and much of the FLASH memory it is good to have an SD card for mass storage if you want to have more than one image.

What limitations occur if the SD card is not used (not inserted)?

Your storage space will be very limited.

Thank you. it sounds like the SD card is a good idea.

Another question: I expect the UNO to place data into the SD card, and then the TFT controller would use it to construct the output for the display. Is that the way it works?

4

louarnold:
I expect the UNO to place data into the SD card, and then the TFT controller would use it to construct the output for the display. Is that the way it works?

Typically the images would be constructed offline on a PC. The UNO would then copy images from the SD card to the TFT.

5

johnwasser:

louarnold:
I expect the UNO to place data into the SD card, and then the TFT controller would use it to construct the output for the display. Is that the way it works?

Typically the images would be constructed offline on a PC. The UNO would then copy images from the SD card to the TFT.

Ahhhh, I see. Pitty that I have to feed the TFT controller, but such is life.