FPGA audio interface conversion circuit diagram

Industrial Router Crystal 3.2*2.5mm 3225 26M (26.000MHZ) 12PF 10PPM 20PPM 30PPM

Single chip microcomputer STM32L151CCU6

L0504-Murata muRata common mode inductor 90Ω 150mA

The FPGA-based audio interface conversion circuit is a modern solution that leverages the flexibility and speed of Field-Programmable Gate Arrays to implement PCI-to-I2S signal conversion. This design eliminates the need for dedicated protocol chips, simplifying the overall system architecture while improving performance and reducing board space. The system is built around key components such as the stereo audio codec TLV320AIC23B, the FPGA XC6SLX75, and the PowerPC8270 processor. Data flows from the CPU through the PCI bus to the FPGA, where it is processed and sent to the audio codec via the I2S protocol. This allows for high-quality audio playback with minimal latency. One of the key advantages of using an FPGA is its ability to generate custom clock signals for different sampling rates. By utilizing the Digital Clock Manager (DCM), the system can dynamically adjust the clock frequency based on the audio file being played, ensuring compatibility with various formats such as 16 kHz and 32 kHz WAV files. Additionally, the use of FIFO buffers helps manage the data flow between the high-speed PCI bus and the slower I2S interface, preventing data loss and ensuring smooth playback. The I2C interface is used to configure the audio codec’s registers, allowing for fine control over parameters like volume, power settings, and sampling rate. The system was tested by loading audio data into the CPU's Flash memory and transmitting it through the FPGA’s FIFO buffer. Simulation results confirmed that the system operates correctly, producing clear analog output suitable for headphones or amplifiers. The implementation proves that FPGA-based solutions are not only efficient but also highly adaptable for future enhancements such as DMA support, right-aligned I2S, and even voice recording capabilities. Overall, this design demonstrates how modern embedded systems can benefit from the flexibility and performance of FPGAs, offering a scalable and cost-effective solution for audio interface applications.