A modular and reconfigurable embedded computer system for designing and prototyping electronic musical interfaces is presented. The system is based on an ARM7 microcontroller that configures peripheral devices, collates input signals, and processes/synthesizes audio. Peripheral devices, each equipped with its own processor, are fully reconfigurable enabling processing and conversion of both analog and digital signals. Communication between the ARM and the peripheral devices is accomplished using the I2C protocol, allowing for multi-master-slave operation. Although the system operates without the use of a personal computer, a serial interface was implemented to facilitate prototyping with a computer terminal running a text or graphicsbased user interface. Applications for this platform include a standalone electronic musical instrument and an augmented acoustic trumpet.