Simple wav playing device implementation - based on atmega32. Supports only 8bit/8khz/mono wav files (16bit/44khz/stereo is a standard now), because of the hardware limitations.
Device use SD-card through SPI interface, supporting FAT16/32 filesystem. Uses popular library fat-fs: http://elm-chan.org/fsw/ff/00index_e.html.
In addition device use 1.8 tft screen with resolution 128x160: https://www.displayfuture.com/Display/datasheet/controller/ST7735.pdf. It's managed by the library https://github.com/cpldcpu/uTFT-ST7735.
To convert digital data from microcontroller do analog format, device is using r2r resistor ladder DAC (digital to analog converter). https://en.wikipedia.org/wiki/Resistor_ladder.
To keep voltage constant and to supply enough current for headphones or speakers device is using 4 amplifiers: http://www.ti.com/lit/ds/symlink/tlc271.pdf
Device has 3 tactile switches on board to navigate in filesystem or choosing song to play. One can also pause/resume/stop playing. Volume can be regulated using included potentiometer.
mkdir build && cd build
cmake ..
make
Will result in building executable, which can be uploaded to device.
make hex
make upload
After building a project will result in uploading code to the device.
mkdir docs && cd docs
cmake ..
make doc
Will result in build documentation.
