Digital sound recorder with ARM microcontroller and SD card

This paper describes how to record, store and play back sound using ARM7 microcontroller LPC214x series with A/D converter and SD card. This paper shows in detail the usage of the A/D converter for signal processing, the Serial Peripheral Interface - SPI - for accessing the external SD card and the D/A converter for play back. Typical applications that would require one or more of these blocks are temperature loggers, telephone answering machines, or digital voice recorders.