DMC worked with CDI through the development process to deliver a reliable, efficient, and flexible platform. DMC also developed Windows-based software to allow easy configuration and setup of the devices.
The end system is both low-powered and capable of handling high-speed data. Circuit design, part selection, and software architecture were all optimized for high battery life. Robust I/O circuitry allows the same I/O pins to be used for several different communication protocols (USB Client, UART, Raw Signal Output, Mitutoyo Digimatic, and a client-specific protocol). Advanced power handling circuitry allows the system to run from power over multiple sources (internal battery, from data connections, including USB, and from a DC-power jack).
DMC and CDI evaluated several microcontroller technologies and settled on the Texas Instruments MSP430 family of devices. When the gage spindle is moving, positional data comes in at a very high speed, reaching the MHz range. An Actel Igloo series FPGA was selected to handle this high-speed data.
Firmware development was conducted with flexibility in mind. Each of the core aspects of the gage functionality are encapsulated in an independent module. Platform-specific calls are abstracted in a separate layer, allowing the main code to encapsulate just generic functionality, rather than nuances of the specific microcontroller device. This allowed for faster software development, and also will allow easier migration to a different platform, if desired in the future.
Development of the new PCB was performed using Altium Designer, a very powerful software suite that includes both schematic capture and layout tools. Altium’s 3D-modeled preview of the board and populated components allowed for quick verification that the component physically fit into the gage before prototyping.
Throughout the prototype process, the system was tested not only for functionality, but also for electrostatic discharge compliance. Advanced shielding and grounding techniques were used to guarantee data integrity, even at very high ESD voltage levels and power supply noise. The final design is remarkable in that it is very tolerant of adverse operating conditions, despite its very compact design.
To facilitate simplified factory configuration and testing, as well as in-field upgrades, DMC developed a simple, yet powerful desktop interface for the gage. Written using the Microsoft .NET framework and using the Windows Presentation Foundation (WPF), the application can be used to upgrade the device firmware and import/export factory configurations. There is integrated user access control so that the program can be provided to OEM vendors for offsite configuration.
Learn more about DMC's Texas Instruments design services.