“For reasons which will become clear later, I ‘d like to exchange data quickly between an STM32 µC and an FPGA. SPI is a serial bus, which can be pushed to several dozen Mbit/sec - but what if we want more? Suppose we could ‘map’ the FPGA into the STM32 ‘s memory space and then simply read and write bytes? No handshaking, no interrupts, no polling. One advantage of such an approach, is that it could transfer data really quickly through DMA - without tying up the µC ‘s CPU at all. As it so happens, most STM32 chips with 100 pins or more include a ‘Flexible Static Memory Controller’ which can do just that. And in an earlier weblog post I already used DMA to pump data into the (built-in) D/A converter at 2.7 million samples per second.”