Wanna connect your STM32 to a parallel interface like a camera but your part does not embed a camera interface ?
Or you want to connect to a FPGA for example or other device with a non standard parallel interface ?
Then you should have a look at AN4666.
It provides detailed implementation using DMA and Timers while minimizing core load.
You can handle a flux up to 10 MHz with a system frequency at 80 MHz on the STM32L4.
Examples available on STM32F4 and STM32L4.
A software Cube extension is available: X-CUBE-PARAL-COM.