MUNICH, Germany — Trade-offs between speed and endurance have in the past limited the use of embedded Flash in applications, in particular in safety-critical ones. Using its non-conducting nitride floating gate, the chip maker has integrated Monos Flash into a 32-bit MCU designed for use in highly safety-relevant automotive and medical devices.
The H8SX/1725F CISC MCU contains 256 kByte high speed Flash for code and another 16 kByte for data. The data section is specified for 30.000 erase/write cycles; if blocks are used consecutively it even can endure 480 kCycles. While this may seem a low figure for RAM write and read cycle numbers in many typical processor-intensive tasks, the Renesas device aims at applications where the data Flash is used to store engine characteristics, performance maps or other specific parameters which are not altered many times over the life cycle, explained Guenter Plechinger, Marketing Manager Consumer & Industrial for Renesas Europe. The company guarantees a 15-year data retention period.
Renesas positions the device against combinations of microcontrollers and EEPROMs. In this environment, users could benefit from the higher integration, lower costs and lower parts count, Plechinger said.
The code part of the on-chip Flash features a very short access time of 12.5 ns, with a roadmap to deliver 10 ns capability in 2009, when the device will be available in a 90-nm shrink version. The short access time allows for single-cycle access by the CPU which in turn makes it possible to run relatively fast applications on the MCU, which currently is clocked at 64 MHz. The 2009 version will support clock frequencies of up to 80 MHz, the company says.
The device has been developed for airbags, electronic power steering, industrial and medical applications. In order to be used in this kind of applications, it meets the reliability specifications described in GHTF Class C and MEDDEV Class III. In order to meet customers demand in these application markets, it sports a rich set of peripheral features ranging from a LIN and two CAN bus interfaces to two ADCs and a 12-channel timer unit.
