VSDBabySoC is a small SoC including PLL, DAC, and a RISCV-based processor named RVMYTH.
VSDBabySoC is a small yet powerful RISCV-based SoC. The main purpose of designing such a small SoC is to test three open-source IP cores together for the first time and calibrate the analog part of it. VSDBabySoC contains one RVMYTH microprocessor, an 8x-PLL to generate a stable clock, and a 10-bit DAC to communicate with other analog devices.
This work discusses the different aspects of designing a small SoC based on RVMYTH (a RISCV-based processor). This SoC will leverage a PLL as its clock generator and controller and a 10-bit DAC as a way to talk to the outside world. Other electrical devices with proper analog input like televisions, and mobile phones could manipulate DAC output and provide users with music sound or video frames. At the end of the day, it is possible to use this small fully open-source and well-documented SoC which has been fabricated under Sky130 technology, for educational purposes.
An SoC is a single-die chip that has some different IP cores on it. These IPs could vary from microprocessors (completely digital) to 5G broadband modems (completely analog).
RVMYTH core is a simple RISCV-based CPU, introduced in a workshop by RedwoodEDA and VSD. During a 5-day workshop students (including middle-schoolers) managed to create a processor from scratch. The workshop used the TLV for faster development. All of the present and future contributions to the IP will be done by students and under open-source licenses.
A phase-locked loop or PLL is a control system that generates an output signal whose phase is related to the phase of an input signal. PLLs are widely used for synchronization purposes, including clock generation and distribution.
A digital-to-analog converter or DAC is a system that converts a digital signal into an analog signal. DACs are widely used in modern communication systems enabling the generation of digitally-defined transmission signals. As a result, high-speed DACs are used for mobile communications and ultra-high-speed DACs are employed in optical communications systems.