If you consider µCs to be incapable of any “serious” data handling, then you’ll be in for a treat.
The following design was created for an upcoming project, which needs a fairly high-speed path for handling requests and transferring 512-byte blocks of data to and from an SD card.
One option is to act as a slave-side SPI device. Here’s how SPI works, courtesy of Wikipedia:
Note that the master drives the clock which causes both shift registers to exchange each bit.

Hi,  I am trying to figure out a way to improve the speed of a SPI based LCD driver for ILI9341. It takes >300ms to update a portion of the LCD on STM32F401RE, with SPI clock at 50MHz.  The options seem to be either use DMA or use parallel port. Can anyone offer some ballpark estimate on how much faster DMA or parallel port is than SPI without DMA?  @hudakz, can you offer some input from your work on:  https://os.mbed.com/users/hudakz/code/ILI9341_STM32F4/  Thanks.