Highly reliable, high speed MONOS Flash 32-bit MCU aimed at safety-critical automotive and medical applications

The endurance of the data Flash is 30,000 erase/write cycles, or 480kcycles if blocks are used consecutively. The non-conducting nitride floating gate helps make MONOS Flash extremely reliable. With this technique it is impossible for a defect to have a negative effect on the charges trapped at nitride layer. Only charges near the defect/disturbance are affected.

The H8SX/1725F eliminates trade-offs between speed and endurance that have so far limited the use of embedded Flash in applications. Through the application of its proprietary technology, Renesas has developed high-speed flash memory capable of random access at up to 100 MHz, and the H8SX/1725F has 256 Kbytes of this high-speed flash memory on-chip for program storage use. This allows 1-cycle access by the CPU even at 80 MHz operation, enabling programs to be executed at high-speed, and thus making it possible to implement high-performance systems. This flash memory can be programmed at high speed within a temperature range of –40ºC to 85ºC , and the 256-Kbyte programming time has been reduced by approximately two-thirds− from approximately 10 seconds to approximately 3 seconds − compared with Renesas's current H8SX/1520 Series. This contributes a throughput improvement of programming process.

The H8SX/1725F also has on-chip data flash*2 − that is, flash memory for data storage − for which 15-year data retention is guaranteed after 480,000 program and erasure. This memory can be used to replace external EEPROM (electrically erasable and programmable read only memory) previously provided for data storage purposes, helping to achieve both parts count and cost reductions. This data flash also newly incorporates a background operation (BGO) function that allows program storage flash memory to be accessed by the CPU − making application execution possible − even during rewriting of data flash contents. This enables data flash data rewriting to be performed efficiently when the CPU is operating.

The H8SX/1725F has been developed for airbags, electronic power steering, industrial and medical applications. It also has the high reliability that Class C (according to GHTF classification) and Class III (according to European MEDDEV association classification) medical applications demand. *3.

The H8SX/1725F operates from a single 5V power supply, which helps reliability because of the high signal-to-noise ratio (SNR). The modern CISC H8SX CPU core has 8 general purpose registers, each 32-bit wide and delivers 1 DMIPS/MHZ performance, which is fully supported by the zero-wait MONOS Flash as well as by the fast 24KByte RAM. The H8SX CPU also has a 16x16-bit multiplier/divider hardware that greatly benefits the execution speed of DSP-type maths algorithms.

The peripheral set comprises a 4-channel DMA controller, a flexible DMA-style function called Data Transfer Controller (DTC), 2-channel CAN, 2-channel SCI, 4-channel High-speed serial interface, a 16-channel ADC, and a watchdog timer. It also features a Programmable Pulse Generator (PPG) that has real-time outputs to drive stepper motors. The device has 61 GPIO as well as 17 inputs.

Of particular note are the strong timer resources. The device saves you from the headache to run out of timer channels or timer functionality by providing no less than 12 channels of 16-bit timers with a 16ns resolution, that can manage up to 32 inputs or outputs. Channels can also be cascaded to 32-bit, buffered for lower interrupt load or generate up to 15 PWM. Finally, there is a phase-counting mode for quadrature encoders.

The H8SX/1725F is now available in a RoHS compliant 100-pin LQFP. It is supported by Renesas’ popular E10A-debugger. An evaluation board SDK1725 is under development and planned to be available in November 2008.