This audio player project is very simple and only need few wires to be soldered. The main part is 8-pin microcontroller and SD memory card. The chip use ATtiny05 series (25/45/85) 8-pin AVR microcontroller. The AVR has two fast PWM outputs in 250kHz carrier frequency that can output wide frequency range audio signals. As storage, the project use SD memory card 4GB. The SDC can be controlled with only six lines, two for power supply and four for control signals. It can also be easily attached to 8-pin microcontrollers.
The project used Petit-FatFs module branched from full featured FatFs module to access the SD card. The Petit-FatFs was developed for very small memory system that available RAM size is less than 512 bytes. Petit-FatFs is suitable for tiny AVRs based project.
Project documentation, schematic and firmware