Custom in-system firmware upgrade for MSP430 Microcontrollers family using SPI

During an embedded system software development, the process of upgrading and downloading the software to the system hardware is fairly easy, because the platform is not encapsulated on its final production form yet. Hence, when the product is ready to be shipped to the end user, an ISP (in-system programming) to upgrade software is needed to add a new feature or to fix a bug. A certain microcontroller ISP interface is UART (Universal Asynchronous Receiver/Transmitter). This microcontroller is a part of a bigger embedded system in which UART interface is not available, the available interface is SPI (Serial Peripheral Interface) only. In this paper, a custom in-system firmware upgrade approach using SPI will be described for the MSP430 Texas Instrumentations Microcontrollers family.