With the ARM Cortex M based microcontrollers continue to do well in the market, the leading microcontroller chip maker STMicroelectronics takes the growth of its STM32 ARM Cortex M based microcontrollers further higher by expanding into a lot of new applications. ST way of doing that is by providing wide choice of ARM Cortex microcontrollers from ARM Cortex M0 to ARM Cortex M7 in one scale of choice and low-power mode microcontrollers to high performance microcontrollers in the other scale of choice. The low-power mode offering is now expanded into ARM Cortex M4 by offering STM32L4.
This writer talked with Vinay Thapliyal, MCU Marketing and Technical Manager, STMicroelectronics India to learn below points on STM32L4 microcontroller and also market trends in 32 bit MCU:
Vinay says STM32L4 is another leap for STMicroelectronics, and it is the world's best performing microcontroller in its class according to multiple tests. If you look at the general-purpose microcontroller market, it is estimated that the general-purpose microcontroller revenue is estimated to grow from year 2014 to 2017 at a CAGR of 2 to 3%. If you look at a volume growth, it is close to double-digit. Due to ASP pressure, the revenue growth is in single digit. What is driving general-purpose microcontroller market from 2014 onwards is, emergence of new range of applications such as wearable and IoT. Due to the requirement of microcontroller like chip in smart phones with sensor interface, smart phones is also offering good market for microcontroller chips.
If you take wearable market alone, the growth estimate for microcontrollers in wearables is in double-digit rate. Wearables require nearly 100% 32-bit microcontroller chips and with features such as wireless connectivity, low-power modes, security, higher DMIPS performance and all this at affordable cost, so that the end product really sells at customer's preferred price. That's where the leading microcontroller vendor STMicroelectronics offering its MCUs chips with right mix of features.
Fitness bands and wrist watch like wearable devices is one of the best example targeted by ST for its STM32L4. For such applications STM32L4 offers TFT display interface, analog interface such as op amp, ADC and DAC, USB, audio interface. And to ensure wireless connectivity STM32L4 offers 4x SPI ports, USART, LIN, IrDA, modem and 1xSDIO. For ensuring security STM32L4 supports 128/256 bit AES key encryption hardware accelerator.
Other suggested application of STM32L4 is industrial IOT kind of applications where sensors are closely integrated with microcontrollers in process control and any such industrial electronics machine to machine communication areas.
All the above said features of STM32L4 also support another interesting application of smart metering, which also needs wireless communication interface , security, LCD display interface and some good-quality analog functions.
Since safety and security is a growing concern these days, some of the safety and security features in the STM32L4 includes, brownout reset-in all modes, Flash with ECC with status register, anti-tamper detection, unique ID, AES 256 encryption, and software IP protection.
ST also tries to save your development cost by offering its discovery boards at less price. One of the advantage of using ARM Cortex and also STM 32 family of microcontroller is, they don't need to depend on paid licensed softwares, embedded developers can very well use open source software platforms to develop the product.
What the leading microcontroller vendors doing now is packing higher performance and offering at the same cost, what they used to offer a product a year or two earlier. So if the microcontroller chip enhances with some more features the ASP is not really falling. But if the microcontroller chip is mature in terms of its acceptance in the market, the price of those devices continue to fall faster.
The IOT application demands flexibility in connectivity, a layer of security, and also low-power consumption. IOT supporting microcontrollers should operate with minimal interference from people, so that machine to machine communication happens seamlessly. Compatibility is another issue when it comes to IOT, says Vinay.
Vinay says ST's MCUs are very successful in wearable/IoT and such applications where sensor-interface is key factor.
ST microelectronics recently launched ARM Cortex M7-based microcontrollers, which is been seeing good level of customer interest world over and also in India.
You can get 1MB of on chip Flash memory and 128KB SRAM in a package of 3.8mmx4.4mm. Higher capacity of internal flash memory and SRAM makes a lot of sense in case of wearable applications saving the overall size of the wearable device/system.
On EEMBC MCU benchmarking, ST's MCUs score higher and is the best considering all the factors of performance such as both ULP and COREMARK, according to Vinay. One of the microcontroller chip from other MCU vendor score slightly higher than ST's MCU in one of the performance but not in both ULP as well as COREMARK.
STM32L4's power consumption is optimised is such a way that it does't effect the performance of the microcontroller. To give some example, when the microcontroller goes to sleep mode, the time it takes to wake up is also important so that there is no delay in taking some action which will effect on the overall performance of the system. Not only wake up from sleep and also moving from one power mode to other power mode need to be swifter to ensure better performance. ST has got its own Flash memory reading technology called ART accelerator supporting this performance enhancement.
Pic above: Vinay Thapliyal, MCU Marketing and Technical Manager, STMicroelectronics India