In the video you can see the basic firmware functions. First, a breakpoint set at the timer shows how the audio is only updated on every other byte. If we move the breakpoint inside this switch, the debugger stops every time the audio changes. Next, execution halts each time 512 bytes are read from the SD card and the sector changes. A final breakpoint halts execution each time the sector resets to 0.
The next article will be the final functional enhancement to the digital audio recorder. We'll extend this basic circuit to include a microphone and audio recording capabilities.
For complete details of the prototype, see the previous article
in this series. This week's firmware is in the project archive
Program a MSP430 microcontroller
Make a singing MSP430 microcontroller