The battle for the heart of the microcontroller market has been heating up, with new low cost, low power 32-bit offerings emerging, driven by access to key intellectual property blocks and the latest manufacturing process technology. But at the same time, semiconductor suppliers are bringing out more variants of their 16-bit devices to target high volume applications at lower cost.

While the traditional argument has been that 32-bit performance is needed for communications stacks and connectivity, 16-bit devices are charging into this area.

The first fruits of the combination of MIPS Technologies and analogue IP house Chipidea are starting to be seen.

The Chipidea USB2 On-The-Go IP block was used for the recent Microchip 32-bit processor that is based around the MIPS M4K core, providing a key upgrade path to 32-bits for the first time for thousands of 8 and 16-bit Microchip users and bringing the ecosystem of development tools and operating systems to those users.

“Particularly for microcontrollers, the M4K core has MIPS16e code compression to reduce code size up to 40 per cent, and shadow register sets to help facilitate fast interrupt or context switch response,” says Pat Hays, v-p of engineering, MIPS Technologies. “We also worked closely with Microchip to further extend software debugging capabilities with the addition of complex hardware breakpoints.”

The Chipidea deal also brings MIPS other potential customers. It has taken the IP for the high speed consumer HDMI interface from NXP Semiconductor (a licensee of both ARM and MIPS for the Nexperia processor family) to offer to SoC vendors alongside the MIPS processor core.

“We had the transmitter, and we had in the roadmap to do the transmitter first but on the receiver we had the option to buy it in and with NXP we can do more, faster, and by partnering with NXP that gives us a greater traction in the market,” says Luis Laranjeira, director of the embedded peripherals and digital IP division in Portugal. “Our expertise is in migrating across technologies so, for example, we have USB blocks on 45nm, and this deal with NXP allows us to migrate the IP to 45nm and 65nm very quickly,” he adds. “We expect to have the receiver on 45nm in Q3 and the same for the transmitter.”

The move to 65nm and 45nm puts HDMI into high volume designs for the consumer market for the first time.

“It is less than one square millimetre in 65nm and less than 60mW for full operation with a 2.5Gbit/s stream for a 1080p display, and it will support up to 5Gbit/s,”  says Laranjeira.

The deal with Chipidea also brings ARM customers to MIPS. “We already ship to ARM customers using the AMBA bus, and now we open the door to have the discussion on the microprocessor,” he says.

ARM has also been targetting the microcontroller space through companies such as start-up Luminary Micro and Atmel over the last couple of years. Atmel has been pushing very low power, with a series of controllers just launched based around the ARM7 core with embedded power switches that control multiple power islands as well as programmable voltage regulators to reduce power consumption in active and standby modes. The AT91SAM7L series runs down to 1.8V and consumes 0.5mA/MHz typical in active mode when executing code out of its flash memory, and in power down mode it consumes only a typical 100nA.

Toshiba, one of the very first MIPS licensees, has also moved more into the ARM camp with its first low cost ARM-based microcontroller, based around the ARM9 core.

“The main reason we went with ARM was to get the performance, and this gives us 200MHz and video capability,” says Roland Gehrmann, marketing manager at Toshiba in Dusseldorf. 

The new device includes scaling and alpha blending for video and two DMA memory engines for the data throughput to handle H.264 video in real time with 320 x 480 resolution at 15 frame/s or QCIF resolution at 30 frame/s.

The E5 device is aimed at providing a richer user interface, including video, for ovens, fridges, washing machines and even air conditioning units. “For industrial customers the ARM9 is high performance and we haven’t seen any requirement for higher performance,” said Gehrmann.

Renesas Technology believes the need for intelligent motor control in new types of energy-efficient systems will push the adoption of 32-bit microcontrollers for motor drive circuits. A 32-bit MCU with a real-time operating system and comms interface support can be used to run energy-saving algorithms which can improve the efficiency of the motor.

The SH7142F microcontroller integrates the company’s MONOS flash which brings the benefit of deterministic 80MHz zero-wait operation yielding over 100 Dhrystone MIPS CPU performance.

But the 16-bit MCU vendors are fighting back with more variants and lower cost options.

Renesas continues to push the 16-bit H8S core, adding USB and Ethernet for the first time by using the cores from the 32bit SuperH family. “Communications is more and more important and we are finding that customer are requesting we stay with 16-bit and do not want to convert to another architecture just to replace an RS232 or other serial protocol,” says Wolfgang Kattermann, group marketing manager at Renesas Technology.

Taking a different route and stripping out the Ethernet and USB, Cambridge-based 16-bit microcontroller maker Cyan has launched a low cost version of its eCOG controller. This allows Cyan to use a smaller, cheaper package and bring the cost down to around $3.

With the move into high volume industrial and portable applications, microcontrollers are even more important, providing more connectivity to a wider range of devices than ever before. The gap between the cost of 32-bit and 16-bit has narrowed considerably, with new IP blocks helping both to provide the performance at the right price point, and both having well established development tools.

While 16-bit has traditionally had the edge in the power consumption, new 32-bit low power variants are challenging that dominance and using the consolidated IP blocks to provide even more functionality.