Read-While-Write Flash adopted by automotive instrument cluster

Among these memory devices, the MX25LW5124G Read-While-Write Flash is selected by Renesas for its high-end RH850/D1M1A automotive instrument cluster microcontroller (MCU) for Over-The-Air (OTA) update. The RH850/D1M1A is part of Renesas’ RH850 Family of MCUs that offers high performance balanced with very low power consumption over a wide and scalable range of automotive products.

Macronix’s Read-While-Write (RWW) Flash offers a suited solution for Over-The-Air (OTA) update applications, which are becoming more prevalent within Automotive Cockpit solutions. Automotive Electronic Tier one’s are striving to meet end customer demand for the most updated features and changes in safety standards. One of the most cost effective method is to have regular updates via OTA. During an OTA operation, the instrument cluster system might update data and code while in mid execution. 

In the past, to implement an OTA update, a system would typically execute a simultaneous RWW operation in two separate Flash devices, by writing to one Flash device while reading from another Flash device. In this scenario, the system would have to reserve double the normal bandwidth, which of course will lower performance, but also require significant redundancy in terms of Flash memory capacity.

The MX25LW51245G RWW Flash from Macronix provides multiple bank architecture with simultaneous RWW capability that allows read access from one memory bank while writing to another memory bank. This feature enables the system to continue executing during the OTA update process happens in the background; furthermore, the system can roll back to its original firmware in the event of an OTA failure or data corruption.

Renesas has implemented dedicated octa peripheral interface to support Macronix memory devices with Serial Multi I/O, including the RWW Flash memory. Macronix’s RWW Flash memory is key to enabling customers to offer an effective, high performance and cost effective OTA solution for a new generation of Instrument Clusters which will dramatically enhance the driver experience by offering configurable clusters with regular updates. Macronix’s RWW Flash memory solutions are manufactured with its own ultra-reliable, high quality 55nm Floating Gate technology, which is part of the ten year Macronix Product Longevity Program (MPLP).