Renesas Technology America, Inc. recently introduced a new 32-bit microcomputer (SH72546R) for powertrain control, boasting of the size of its on-chip flash (3.75MB). It’s compatible with its predecessor, SJ72531, which has 1.25MB of on-chip flash. Performance is up to 400MIPS when operating at 200MHz.
Ever larger on-chip flash is a significant trend in powertrain MCUs and suppliers are planning 4MB devices. Infineon says its AUDO FUTURE family includes the 180MHz TC1797 with 4MB of flash and integrated FlexRay controller, as well as the 133MHz or 80MHz TC1767 with 2MB of flash, and the 80 MHz TC1736 with 1MB. Freescale Semiconductor says its MPC5674F, based on a 264MHz core, also includes 4MB of on-chip flash.
On-chip flash is only one parameter, of course, but it’s an important one. Amrit Vivekanand, segment marketing manager, powertrain solutions, for Renesas’ automotive business unit, explains that larger on-chip memory configurations are needed to accommodate today’s larger, more sophisticated algorithms, which process more data from more sensors for more precise engine control, all for better fuel economy. Vivekanand adds that more flash is also valuable in compensating for the 10-30% overhead that often comes with automatically generated code.
Renesas’ SH72546R also includes a low power cache, and 128KB of flash memory with functions essentially equivalent to those of EEPROM for data storage, lessening the need for external memory, according to Vivekanand.
The SH72546R, now in production, is able to withstand high environmental temperatures, which Vivekanand says is difficult to achieve in MCUs with on-chip flash memory. The chip is fabricated using the 90nm process node and can operate at 200MHz at temperatures up to 125°C with low power consumption, so it can be mounted in high-temperature engine or transmission environments.
Peripheral functions include a multifunction timer (ATU-III: Advanced Timer Unit III) that is useful for both engine and transmission control; a high-speed 12-bit A/D converter; CAN interface, and high-speed serial interface functions.