Gavin Turner
gbturner@gmail.com
This project was built by Gavin Turner in the summer of 2022 during an internship at GlobalFoundries' electrical failure analysis lab. The goal of the project was to develop a simple communications interface that would allow for quick screening of product fallout through die level probing. The interface was built specifically for the communications through the MIPI RFFE protocol as outlined by the MIPI alliance, but software modifications could allow for communciations with any protocol requiring four channels or less.
- Implement easy to use functions for read, extended read, write, extended write, bus park, and assert SSC
- Supply and monitor VDD and VIO (1V to 3.3V up to 5mA)
- Adjustable logic levels on DATA and CLK pins (1V to 3.3V)
- Utilize an RP2040 microcontroller
- Implement solution on a PCB with BNC connectors for ease of use with micromanipulators during probing
The core of the software solution is an API implemented through the use of a C++ header file.
This header file defines a custom class named RFFE_master. This class builds upon a variety
of private functions to enable the user to "bit bang" dataframes with occordance to the MIPI
alliance specifications. The software allows for low speed communications with a DUT with active
power supply monitoring to characterize defective parts. The final software solution can be viewed
in the MIPI.h and MIPI.cpp files as well as application examples in the source_code folder.
The hardware solution implements 4 MCP4725 ADC's for variable logic levels and power supplies, 2 INA219 current shunts monitors for active power supply monitoring, 1 OLED display for data output, 1 TCA9548 I2C multiplexer to manage communications with peripherals, and 5 BNC connectors for easy connection to micromanipulators. All components are integrated on a standalone PCB with an on board RP2040 based microcontroller. The final hardware implementation can be viewed in the board_files folder