Cai Biesinger

At the end of our VLSI intro class, I designed schematics and layout for a 13x16 register file with a partner.

We designed schematics and layout for the register file, and schematics for the ALU.
Design was done in Cadence Virtuoso, simulated in hspice.

Some aspects of our design:

• 100% custom cell designs
• 100% manual placement and routing
• Local word and bit lines used to cap fanout at 4
• Smallest design area in class
• Carry-Skip adder for excellent 16b-word performance
• Gate sizes iteratively optimized for power and delay minimization via simulation

We won 1st place in a Micron-sponsored design contest.

Implemented 5-stage pipelined 64-bit ARM CPU in SystemVerilog as class project. We implemented a subset of the real ARM instruction set.

• Included accelerated branch execution and data forwarding for only 1 delay slot after branches and loads
• Testing was conducted partially automatically via tasks and asserts
• Final verification done via real programs run on simulated CPU
• Used interfaces and modports for significant code simplifaction
• Datapath was written in gate-level Verilog
• Control signals was written in RTL

Frustrated with the outdated and partially-implemented scripts available to convert GDSII IC layout database to SVG vector files, I created my own from scratch. It supports hierarchial layouts, and is optimized for use even with very large designs.

This allows for viewing IC layouts in traditional vector graphics editing programs, or printing layouts at any scale without loss of quality. Initially created to allow layouts to be printed onto posters, while still being able to see all details viewed up-close.

Specified, designed, laid out, assembled, programmed, and tested hardware and software for future animal call research. Iterated on previous design which did not meet requirements.

STM32-based embedded system for real-time analysis of frog calls. Used DSP to remove background noise, and distinguish different species of interest. Design is cheap, efficient, and extremely scalable. Processes data in real-time with minimal delay, then uses RGB LED to transmit data to camera for processing and analysis. Device is wirelessly configurable in the field to avoid needing to approach the animals/devices, which would interrupt the experiment. Highly optimized code and power-saving hardware means device can run for 50-100 hours on 1 pair of AAA batteries.

The science module is used to acquire a variety of environmental readings, as well as extract & analyze soil samples during the competition task. The team builds a miniature mars rover to compete against other teams in a set of challenging tasks.

I specified, designed, laid out, assembled, programmed, and tested hardware and software for the science module on the team’s 2018-19 year rover. Integrated entire panel of components to a single PCB, making the system much smaller & robust.

Features of my design:

• Controlled by on-board Raspberry Pi
• 4 motor drive outputs, each capable of 30A with precise current measurement
• 3 sets of encoder & limit switch channels
• 4 isolated servo motor drive channels
• Connected to 6 different sensors using I2C, SPI, and an ADC
• 4 PWM-driven RGB LEDs for status
• Onboard regulation to allow entire system to be fed by a single 24V connection
• Small form factor: 8.25 x 3.5"
• 2-layer PCB for cost reduction
• Easy-to-use GUI allows any operator to easily control the module during competition
• Built-in graceful handling for poor wireless connection quality
• Cheap USB microscope with servo-driven focus system, with software to auto-focus image

The professor teaching EE271 (Digital Circuits and Systems) approached me to design a PCB for students taking the class, for use in their final project. The module was to have a 16x16 red/green LED matrix connectable to the FPGA development board (Altera DE1-SOC). Previously, students would be expected to manually wire up an 8x8 matrix, and wiring errors ended up being an excessive time-sink for students and TAs that was deemed a poor use of time. A simple plug-in module with a larger matrix would help to increase the options available to the students, and alleviate the hardware problems.

I designed the PCB and wrote the Verilog driver for all future students to use.

The board has been used for several classes since then, with great success.

While taking EE331 (Devices and Systems I) I took the final project that our group designed and built on a breadboard, and made a PCB to present it. The class had absolutely no requirement for PCB design, I just made one because I enjoy doing it. I also uploaded a timelapse video of me designing the board, available here.

The professor in charge of creating a new class, EE201, contacted me to get help writing a PCB design tutorial for future EE students to learn from. I wrote a tutorial that guides students who have little EE knowledge through the entire process, from schematic capture to gerber file export. This will help them gain more practical skills, and get them thinking about real-world circuits.