Building on its existing FM3 family of MCUs, the FM4 family from Fujitsu Semiconductor offers products with even greater computational performance and enhanced peripheral functionality. The digital signal processor (DSP) and floating-point unit (FPU) that come standard in the Cortex-M4 core provide the new microcontrollers with the power needed to handle advanced, complicated computations.
In addition, the algorithms for operating internal flash memory have been redesigned for greater speed and lower power consumption. Compared to the existing FM3 Family's High Performance Group, the new products offer at least four times the processing power while reducing the per-frequency power consumption by half.
- A wider bus for internal flash memory allows for read access with no CPU wait states, thereby delivering both faster processing performance and lower power consumption. The lineup maintains the same quality standards as previous generations, with 100,000 rewrite cycles or 20 year data retention guaranteed.
- Because the calendar circuit and 32-kHz generator circuit are on their own independent power supplies, the current required when running the real time clock (RTC) can be held to roughly 1.5 µA. This allows devices in the family to be used as power supply controllers as well.
- The analog circuitry has been redesigned from the ground up. The accuracy of internal oscillators has been held to ±2% thanks to a trimming function; the D/A converter can convert with 12-bit resolution; and the A/D converter features twice the conversion speed as before
- The timer for three-phase motors, known as a multifunction timer, features a number of enhanced timer functions, including support for asymmetric pulse-width modulation (PWM) waveform output and multiple A/D start triggers. At the same time, the minimum resolution is improved to 6.25ns.
- Together with the improvements to the A/D converter, these enhanced timer functions enable even more precise motor control while helping to improve the energy efficiency of motorized devices such as industrial equipment and household appliances.
- To accelerate SPI communications, support has been added for data transfers at up to 20 MHz. Moreover, variable data lengths have now been expanded from the previous maximum of 9 bits to 16 bits.
- A DSTC circuit has been added to enable high-speed data transfers that bypass the CPU. This circuit uses a descriptor method in which, by following descriptor commands previously constructed in memory, it can directly access memory and peripheral devices to transfer data. Through sequential operations, it is possible to reduce the size of software (ROM capacity) and reduce power consumption when the system is running.
- In terms of external memory connectivity, the FM4 Family continues to support SRAM, NOR flash and NAND flash, in addition to providing added support for SDRAM. It also supports SDIO interfaces, such as SD cards.
- The new lineup supports both 3V and 5V power supplies. The work memory (32 KB) included in some FM3 Family products is also embedded as a standard device. It can be used to back up system parameters or data logs, and through the use of an EEPROM emulation library, it can eliminate the need for external EEPROMs.
Fujitsu Semiconductor will exhibit the new products at Embedded Technology West 2013, beginning June 13, 2013 at INTEX Osaka .