Real-Time Operating Systems (RTOS) and their applications
For development of low-volume fixtures on the manufacturing floor, developers can use an ESP32 development board. These boards range from very basic ‘getting started’ boards to sophisticated boards that include secondary processors and LCDs. There are some that are also well suited for industrial automation applications, assuming simplicity of development is a key requirement. For instance, there’s the ESP32- DEVKITC-32D-F (Figure 3). This is a simple breakout board for the WROOM-32D that has all the power conditioning and programming circuits a designer or developer needs to get started. The board is powered either through an on- board USB micro connector or through the V-IN breakout header. Jumpers or wires can then be used to connect various components to the WROOM-32D. Another example is the Adafruit Industries Airlift ESP32 Shield. This not only includes the WROOM- 32D, but also has additional prototyping space (Figure 4). This prototyping space can be used to add connections to other shields in addition to adding custom circuitry. A developer could use this area to build input and output circuits for low voltage industrial automation applications. There is also an onboard SD card connector that makes developing a data logging application that much easier.
an external antenna that they can arrange within their product for optimal RF characteristics. An interesting point about the WROOM-32D modules is that they also come in various flash memory sizes. The modules come in additional memory support variants like the ESP32-WROOM-32D with 8 Mbytes and the ESP-WROOM-32D with 16 Mbytes. Selecting an ESP32 development board for industrial control The ESP32 modules are a great choice when designing a board that will be used in production or where they will be put on a board that will be used in ‘high’ volume.
Figure 5. The Digilent ESP32 PMOD board provides the ESP32 module in an easy to connect expansion format for use with other processors and development boards. Credit: Espressif Systems
Figure 3. TThe ESP32-DEVKITC-32D-F development board includes breakout headers for connecting to any of the WROOM-32D pins and can be powered through USB for development purposes. Credit: Espressif Systems
peripherals. The processor actually has two processing cores whose operating frequencies can be independently controlled between 80 megahertz (MHz) and 240 MHz. The processor’s peripherals make it easy to connect to a range of external interfaces such as:
additional hardware and layout complexity associated with an IPEX connected antenna. However, if the IPEX connector option is selected, there are plenty of good antenna options, such as Inventek Systems’ W24P-U.
automation applications where a development board with an additional processor is being used and the ESP32 will just be providing connectivity rather than handling the whole application load. In these applications, the development board or product may have expansion PMOD connectors onboard. Rather than custom designing a PMOD board for the ESP32, developers can leverage the Digilent ESP32 PMOD breakout board (Figure 5). The ESP32 PMOD provides a PMOD standard connector along with the following:
■ Four pin I/O expansion ■ Jumpers for boot configuration The Espressif Systems ESP- WROVER-KIT provides a full ESP32 development solution with everything designers need to develop an ESP32-based application (Figure 6). For example, the WROVER includes an FT2232HL USB to serial converter from FTDI which makes it easy to program the ESP32 module without the need for custom programming tools. The board also includes an onboard 3.2 inch LCD, a microSD connector, an RGB LED and a camera interface. The development board also as all the I/O lined up and made easily accessible through pin headers.
The module contains 4 megabytes (Mbytes) of flash and has 38 pins that are arranged to minimize the module’s size, making it nearly square. In fact, the WROOM- 32D is completely pin compatible with the ESP- WROOM-32U (Figure 2). The WROOM-32U replaces the onboard PC board trace antenna with an IPEX connector, based on the Hirose U.FL design. In doing so, the WROOM-32U saves board space and allows developers to connect
■ SPI ■ I2C ■ UART ■ I2S
■ Ethernet ■ SD Cards ■ Capacitive touch
There are several different ESP32 modules that a developer can select based on their application needs. The first and most popular ESP32 module is the ESP32- WROOM-32D, which runs at up to 240 MHz (Figure 1). The module includes a PC board trace antenna, which simplifies implementation. It also avoids having to add the
Figure 4. The Adafruit Airlift ESP32 Shield allows designers to prototype their design or build one-off circuits that can be used in industrial automation applications. The Airlift includes prototyping space that can be used for dedicated circuitry. Credit: Espressif Systems
■ A power LED indicator ■ An on-board user button
There may be some industrial
we get technical
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