Creation of an ARM© Cortex©-M Based Microcontroller for Downhole Electronic Systems

Abstract

Abstract This paper will describe the development and testing of a new ARM® Cortex®-M based microcontroller for high temperature downhole electronic systems. The trade-offs in the selection of each on-chip peripheral will be discussed with respect to their requirement in the application. Particular detail will be afforded to the underlying high-temperature implementation technology that allows reliable operation at extreme temperatures. High temperature and electrical overstresses can cause latch-up in CMOS devices that will interfere with normal device operation or destroy the device. For reliable operation in the downhole drilling environment it was necessary to immunize this device against latch-up using an innovative processing technique. Details on the qualification and testing of the product to ensure that it meets the challenging environment will also be discussed. This includes electrical testing and temperature cycling testing to ensure that the different package options for the silicon device are mechanically sound in a high temperature environment that exposes the silicon and packaging materials to thermal cycling. The ecosystem for the microcontroller will also be discussed – hardware and software development tools are required to optimize the use of the device in a downhole drilling embedded system. A set of companion components is also required to operate with the microcontroller in the high temperature harsh environment. The components that were selected for use on the high temperature test boards will also be discussed.