I was running into issues with SPI bandwidth limits with a specific microcontroller I have been asked to use. It was limited to 6MHz SPI frequency which was limiting me to a 128 by 128 display with 16 bit color ( I had a requirement of 30 FPS to meet).

The idea being I have a Touch panel with an LCD screen. I am using a dedicated touch controller that sends info to the main micro which puts the display on the screen.

I cannot change the main micro as it is being used for all sorts of other things.

At the minute I have been forced to use MIPI-DSI as it solves bandwidth issues however it increases costs with screens available with MIPI being more expensive than SPI.

A thought was to use a second cheap micro which has a higher SPI bandwidth to fix the problem.

My friends doing the software aspects have informed that while this would fix most use cases, it wouldn't work with animations (which you'll have if your touch screen has swipe) as it would require dedicated GPU.

Does anyone have any other solution fix around this issue? Could I get a touch controller that handles both touch detects as well as the graphic side?

Sorry for keeping it cryptic but I hope this is enough information to help.

  • \$\begingroup\$ Another option, that is also probably more expensive: You could use an 'intelligent' display instead. These displays have built-in controllers to off-load display processing from your uC (also decreasing the required BW). You can also usually pre-store graphics and routines, and things like the touch controller, joy stick, buttons, and dio are built in. One manufacturer of these things - that comes to mind - is 4D Systems (no affiliation), but there are others as well. \$\endgroup\$ – Chris Knudsen Aug 29 '18 at 12:11

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