I have not written any new post for a while, so here is one more project for the stm32f4 discovery. I prepared this post a long time ago, but for some reason I never posted it, so here goes:
Based on one of the examples provided by ST, I have written a program for the STM32F4 Discovery board that plays MP3 files from an USB memory stick. You can download it STM32F4_USB_MP3.zip
If you use a usb-host cable such as this one you can connect an USB memory stick (with fat32 file system) with mp3-files to the micro-usb port of the stm32f4 discovery. The files should then be played one by one. The user button can be used to skip to the next file.
If you follow this tutorial you should be able to build and upload the provided files right away.
The main.c-file has many comments, so hopefully you can figure out how it works. Using a USB-memorystick for logging is quite easy with this program as a basis. Only the two usb-pins, 5V and gnd are required to connect it to any stm32 with USB support, so hw-wise it’s even easier than using an SD-card.