A little while ago I got one of the fairly common “Nokia 5110” LCD modules, a 84×48 b/w graphic LCD screen, thinking it would be handy to have in current or future projects. One of the things I especially like about this module is that it is using a serial protocol (SPI) to send data and control messages. This reduces the number of pins required tremendously. When I finally got around to playing around with it, I managed to get it to work with my STM32F4-Discovery board fairly quickly. I could have left it at that, but the code I was using during my initial tests was rather crude and inefficient, and I thought this module would be a good reason to finally get my hands dirty with the DMA controller on the STM32F4.