There are very few customers that enjoy receiving the statement: “Dear customer, the microcontroller in which you invested years of development time and money and planned to have in production for another 10 years is going End-Of-Life!” There have been several popular microcontrollers and microprocessors that have gone EOL over the last few years as semiconductor suppliers consolidate and prune their product portfolios.
Customers have the choice of performing a last-time purchase or re-designing the product. Last time purchases are problematic in the areas of up-front cash outlays and forecast quantities. As far as redesign, a simple board layout change to support a different part is easy, but software compatibility is the major hurdle when moving to a different microcontroller family. Most companies have a large investment in their target software; changing to a new architecture typically requires a complex and costly software port as well as verification.
Lattice to the Rescue
Lattice recently helped a customer in just this situation. The customer had a microcontroller in continuous production for more than 15 years. Not wanting to tie up capital in a last-time buy, the customer looked for other alternatives.

The customer required the replacement to be exactly the same fit and function as the original microcontroller. In addition, external and internal timing, processor functionality and even the same binary program had to run with no modifications. This compatibility included embedded software timing loops in the legacy processor code.
The final hardware solution is a small mezzanine board that contains an instant-on LatticeXP2 FPGA, an ADC device and clock generator. A PLCC connection allows direct interfacing with the manufacturer’s PCB and provides a pin-for-pin replacement for the original microcontroller. As the LatticeXP2 contains on-chip FLASH memory to configure the logic on startup, there is no need for an external boot memory which reduced the board device count and allowed for a smaller final solution.
The software solution used a third-party Intellectual Property (IP) core from Digital Core Design. DCD is a Lattice IP partner that offers a number of microcontroller and peripheral IP solutions. DCD modified an existing microcontroller core to match the exact execution and peripheral set found on the obsolete device.
The pin compatible solution allowed the customer design team to focus their efforts on validating the IP core instead of performing a full hardware and software design and validation. The solution enabled by Lattice and DCD ultimately saved the customer time and money by not having to perform a total system re-design.
Conclusion
Microcontroller and Microprocessor obsolescence will continue, but fortunately there are easy solutions to the problem using FPGAs coupled with microcontroller IP. The Instant-On LatticeXP2 FPGA provides a secure and small footprint solution that also meet customer’s very long life requirements. Microcontroller IP from partners like DCD allows a very quick and cost effective solution to replace existing microcontrollers while retaining exact software compatible with the original design.