This projects gives you a simple wav player with help of the MMC card connected to ATmega32. You can use any AVR microcontroller.
The MMC card works on 3.3v so a 3.3v regulator is used and the 5v to 3.3v level conversion is done by the combination of resistors. The LF33CV is used for the 3.3v regualtor.
The code is written for 1GB card and if you want to change then you need to change the line number 98 in the program. Now the line is “Test = 512 * 7800” you need to change this 7800 for other value of MMC card.
An 11.05Mhz crystal is used so you have to select the external high frequency crystal at the fuse bits.
The LM386 forms an audio amplifier which amplifies the audio signal. There are 3 buttons on the circuit and they are S1 for start/stop, S2 for Forward and S3 for reverse.
For more Detail: MMC card based WAV player using atmega32