hi,

First of all, let me say that the posted code is useless. Please add comments next time and put your program between tags <PRE> and </PRE>

Now here are some my ideas.

- with current scheme you are not able to obtain good quality of sound. It is because sound quality is limited with the UART speed. For example, if you use internal PLL at 16,78MHz then with your UART configuration it provides 9600 baud. Now divide it on 10 (start bit + 8 data bits + stop bit) and the result is 960 bytes per second. It is very not enough for digitized audio. So either use faster UART or switch to another interface.

- use a buffer for UART routines. It may not be a big one, double buffered one is enough. It helps you to avoid jitter effect.

Regards,
Oleg