Leveraging the LPC55S16-EVK for Industrial ApplicationsAugust 06, 2020 by Mark Dunnett, on Behalf of NXP
Explore the LPC55S16, an MCU well-suited for industrial and professional applications, thanks to its fast clock speed of 150 MHz, out-of-the-box support for communicating over a CAN-FD bus network, and low current consumption.
The LPC5500 series of microcontrollers (MCUs) offers many features to the modern embedded designer looking for a device capable of handling a broad range of applications, from robotics to industrial.
A recent series of articles dove into the features and applications of NXP’s LPC5500 series of microcontrollers, discussing the more advanced functionalities of these MCUs, namely the security mechanisms and multi-core capabilities of the LPC55S69 device. In this article, explore the LPC55S16 MCU, another member of the LPC5500 series that is well-suited for industrial and professional applications, thanks to its fast clock speed of 150 MHz, out-of-the-box support for communicating over a CAN-FD bus network, and low current consumption.
LPC55S16-EVK Capabilities and Applications
The LPC55S16-EVK development board is based on the LPC55S1x MCU family — a streamlined, entry-level family within the LPC5500 series of Arm® Cortex®-M33 based MCUs.
These microcontrollers come with up to 256 kilobytes of flash memory and a single core. It maintains the smaller 64-pin HTQFP package and operates with a clock frequency of up to 150 MHz. The TrustZone extension is also available on this model.
Figure 1. The NXP LPC55S16-EVK evaluation board.
The LPC55S16-EVK evaluation board is slightly larger than the LPC55S69-EVK and does not have a micro-SD card slot. Instead, the new device incorporates a 9-pin male D-sub connector, which allows the development board to communicate over a CAN bus network. The LPC55S16 supports communication over CAN and CAN FD out-of-the-box, making this MCU well-equipped for industrial and professional applications.
Additionally, the evaluation kit contains:
- Two USB ports (one full speed and one high speed)
- Arduino Uno compatible shield connectors
- PMod/host interface port
- MikroElektronika Click module site
- Jumpers, allowing for easy EVK configuration
The evaluation kit also includes a Cirrus Logic codec for audio processing.
The standard toolchain for this development board is NXP’s complimentary MCUXpresso suite of software and tools, which includes an Eclipse-based IDE, configuration tools, and SDKs with examples. However, the LPC55S16-EVK is also supported by Zephyr OS for building secure and reliable IoT applications.
The CAN integration makes this device work well in automotive and industrial applications, ranging from gateways between computers and industrial equipment to elevator control units. The RS485 support, high-speed SPI, and Zephyr OS support further complement this. At the same time, the LCP55S69 MCU focuses on security-relevant and IoT use-cases.
In this unboxing video, learn more about the LPC55S16-EVK and some of its key features.
Investigating the Evaluation Kit’s Power Rails
It can be especially useful to know how much current an MCU requires in a real-world scenario. The EVK has three power rails that supply the MCU: MCU_VBAT, MCU_VDD, and MCU_VDDA.
Figure 2. The EVK's three power rails.
As mentioned above, the kit uses several configurable jumpers. NXP provides a jumper to each of these power rails, making it possible to determine the current consumption of the individual rails. The current consumption of each supply rail must be added up to understand the overall power consumption of the MCU.
- MCU_VDD is set to 3.3V by default. This supply rail drives the I/O pads of the microcontroller, and the current consumption is proportional to the switching speed of the I/O pins (See section 13.1 of the preliminary datasheet).
- MCU_VDDA supplies the internal analog circuits.
- MCU_VBAT is also set to 3.3V by default, and it drives the DCDC converter and power-management unit on the MCU. The current consumption might be proportional to the operating frequency of the microcontroller.
How Fast Can the MCU Go?
In the CAN FD loopback example that comes with the LPCXpresso55s16 SDK, the operating frequency of the MCU is set to 150 MHz. Before determining the current consumption, it’s practical to test how fast the MCU’s clock is to ensure that it can hold up with the manufacturer’s claims.
Within MCUXpresso, the clocks configuration tool can enable the CLKOUT pin and set the CLKOUTDIV to divide the frequency of the free-running oscillator by 250. The output on this pin should be 600 kHz, assuming that the MCU is running at 150 MHz.
Figure 3. The output on the CLKOUT pin should be 600 kHz.
Therefore, it can potentially get more done (compared to a competing product that operates with a slower frequency). This means that the part is more suited for industrial applications, fast DSP calculations, and high-speed peripherals and protocols (like CAN-FD) than a similar MCU that runs at a lower frequency.
LPC55S16-EVK Current Requirements
The CAN FD example doesn’t use any analog circuitry, nor does it drive the IO pads of the microcontroller, so only the MCU_VNAT power rail was measured in this example. With a multimeter connected to JP22, it’s possible to observe that the MCU consumes 7.54 mA at 150 MHz in this setup.
Figure 4. With a multimeter connected to JP22, we see the MCU consumes 7.54 mA at 150 MHz.
The SDK also comes with an audio speaker demo, which turns the LPC55S16-EVK into an external USB speaker that receives digital audio from the USB port and outputs an analog signal to the 3.5mm LINE_OUT audio jack through the Cirrus Logic codec. This setup makes it possible to test the current consumption in a realistic scenario that utilizes the USB interface and Cirrus audio codec.
This time, there was current flowing in the MCU_VDD power rail to the LPC55S16 because the chip receives USB data and transmits it to the codec. The current measured across JP20 was 2.72 mA.
Figure 5. With current flowing in the MCU_VDD power rail to the LPC55S16, the current measured across JP20 was 2.72 mA.
The MCU_VBAT rail supplied approximately 4 mA, meaning that the LPC55S16 can operate in the single-digit milliamps at 96 MHz while executing a practical, real-world application.
The speed and current consumption experiments show that the MCU can get many things done quickly, due to the high clock speed. It also supports standard industrial communication protocols, all while requiring very little power. Therefore, this device works in a wide variety of applications, ranging from industrial devices to automotive applications and consumer products.
The LPC55S1x MCU Family: Versatile MCUs for a Broad Range of Applications
The LPC55S1x family of MCUs is the cost-effective, streamlined variant of the LPC5500 MCU series. These microcontrollers are equipped with up to 256 kilobytes of flash memory, a single core, and support the TrustZone extension. Perhaps the most interesting new feature is the out-of-the-box support of CAN FD, making this CPU immensely interesting for the industrial market.
The LPC55S16-EVK evaluation kit exposes two USB ports and the CAN-bus interface for testing purposes. It also contains headers for Arduino UNO compatible shields and a MikroElektronika Click module site. Besides that, the board incorporates a Cirrus Logic audio codec for multimedia applications.
The MCU can operate with a clock frequency of up to 150 MHz with a very low current consumption. These features make the LPC55S16 a versatile MCU, employable in many applications ranging from individual industrial solutions and automotive applications to mass-produced consumer devices.
There are plenty of software examples available for the LPC55S16-EVK, based on NXP's complimentary MCUXpresso IDE and Software Development Kit (SDK). A growing list of application notes, tutorials, and videos can be found at NXP’s community page.
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