Engage is the ultimate solution for versatile and powerful IoT dashboard applications. It's not just a one-size-fits-all solution. Engage boasts a sleek touchscreen interface enhanced by an advanced vector graphics accelerator, ensuring seamless and dynamic visual interactions. With extensive connectivity options and large RAM and ROM, Engage is ready to handle diverse IoT scenarios, from smart home dashboards and facility monitoring to custom smart devices. Whether integrating into existing systems or pioneering new innovative environments, Engage delivers robust performance and flexibility to meet your needs, adapting to your unique smart dashboard requirements.

Single Board Computers

Industrial Devices

Sensor Modules

Connectivity Modules

Robotics

Environmental Monitoring

Value-Line Devices

Evolve 'R, a highly customizable module carrier, is designed with energy efficiency in mind, providing reassurance. It features sensor and extension ports for flexible device configuration. With 802.15.4 connectivity, it supports BLE, Zigbee, Thread, and Matter. An M.2 port is also available, offering connectivity options like LoRa, cellular, WiFi, and more. The device can run on any lithium battery or a solar panel, with battery charging available through USB-C and an on-board MPPT solar power harvester. This energy efficiency makes Evolve 'R a powerful choice for your remote sensing applications.

Energy Analyzer is a comprehensive solution designed for precise monitoring and analysis of three-phase voltage and current. Equipped with high-accuracy components, it delivers accurate real-time readings and in-depth analysis to optimize energy usage and efficiency. The Energy Analyzer supports wired and wireless telemetry, providing flexible and convenient data transmission for various monitoring environments. Ideal for industrial facilities, commercial buildings, and energy management systems, this device ensures reliable performance and insightful energy metrics to empower better decision-making and enhance operational efficiency.

The Bioacoustics Module is designed to capture, analyze, and interpret biological sounds from natural environments. It provides high-fidelity acoustic monitoring for research and environmental applications. By precisely recording bioacoustic events, this module supports wildlife conservation, habitat monitoring, and ecological research studies.

This sensor module carries ST ISM330BX, a high-performance 6-axis Inertial Measurement Unit combining a 3-axis accelerometer and a 3-axis gyroscope. It offers wide bandwidth and low noise for precise motion tracking and vibration measurement. Additionally, it features embedded AI and sensor fusion capabilities, enhancing its application in industrial environments. The ISM330BX supports Qvar sensing across three separate channels, with configurable processing and filtering options, making it an ideal choice for advanced motion & vibration detection and analysis.

The M.2 BLE 802.15.4 Module is a multi-protocol communication add-on that supports numerous wireless standards, including Bluetooth Low Energy (BLE), Zigbee, Thread, and Matter. This module seamlessly integrates with the M.2 interface, offering a compact and efficient solution for modern IoT and smart home applications. It empowers the next generation of intelligent and connected solutions.

The M.2 LEO Satellite Module uses LoRa technology to enable communication with Low Earth Orbit (LEO) satellites. This compact M.2 module is ideal for global asset tracking, remote monitoring, and environmental sensing applications.

The M.2 Wi-Fi Module is an advanced connectivity solution featuring the latest Wi-Fi 7 technology. This module operates across 2.4 GHz, 5 GHz, and 6 GHz frequency bands, delivering ultra-fast, low-latency wireless communication. Designed to integrate seamlessly into devices via the M.2 interface, it offers unparalleled performance with higher data rates, enhanced efficiency, and low power consumption.

The Wheeled Robot Controller is a powerful all-in-one solution that handles motor control, sensor integration, and connectivity for wheeled robotic systems. This universal board precisely drives robot motors, ensuring smooth and responsive movement. It reads data from multiple sensors, empowering real-time environmental awareness and instant decision-making. The controller also enables network connectivity, allowing for remote operation, and provides internal wired communication for integration within the robot’s computer. Suitable for small autonomous vehicles, delivery robots, or educational robotics projects.

This Value-Line Sensor Carrier Board is a cost-effective solution that delivers essential sensor functionalities without compromising quality. Tailored for projects requiring reliable telemetry at a reduced cost, this board integrates essential features, including optional temperature, humidity, light, hall effect, and motion detection, making it ideal for various applications such as smart home systems, industrial monitoring, and research projects. Despite its streamlined design, it maintains the same quality as our flagship devices. A minimum order quantity applies, and the device configuration can be customized on manufacturing for the deployment's needs.

The M.2 Developer Module is an essential tool for developers and engineers working with M.2 interfaces. This module simplifies access to typically hard-to-reach M.2 data pins by exposing them to user-friendly headers. It is designed to streamline the development and testing process and provides easy connectivity for signal probing, debugging, and peripheral integration.

This Value-Line Sensor Carrier Board is a cost-effective solution that delivers essential sensor functionalities without compromising quality. Tailored for projects requiring reliable telemetry at a reduced cost, this board integrates essential features, including optional temperature, humidity, light, hall effect, and motion detection, making it ideal for various applications such as smart home systems, industrial monitoring, and research projects. Despite its streamlined design, it maintains the same quality as our flagship devices. A minimum order quantity applies, and the device configuration can be customized on manufacturing for the deployment's needs.

The I²C Adapter Module is a reliable solution for seamlessly integrating 5V I/O devices with your systems. This adapter has a high-speed voltage translator and 5V Voltage booster, ensuring robust communication between our 1.8V carrier boards and high-voltage external sensors, such as advanced air quality monitors. This module enhances interoperability in custom IoT applications and is ideal for expanding your system’s capabilities with diverse sensor types.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

The Positioning Module is a compact and powerful solution featuring an integrated miniature GPS antenna for precise geolocation capabilities. This module provides accurate real-time positioning, making it ideal for applications where space constraints and location accuracy are critical. The onboard GPS antenna ensures reliable satellite communication, enabling seamless navigation and tracking for devices in diverse environments. Whether used in asset tracking, autonomous robotics, intelligent transportation systems, or portable navigation devices, the Positioning Module offers robust and efficient geospatial data, significantly enhancing the functionality and effectiveness of your positioning solutions.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

The Presence Module is a cutting-edge solution utilizing miniature radar technology to detect human presence and even the slightest movements with exceptional accuracy. This module excels in various applications, including energy optimization in workspaces, enhancing security systems, ensuring elderly safety at home, and detecting trespassing. Its advanced radar technology provides reliable presence detection and motion sensing, making it ideal for optimizing energy use by activating systems only when needed, securing environments against unauthorized access, and monitoring the well-being of individuals. Moreover, its compact design and high sensitivity make it a versatile choice for transportation security, where it plays a crucial role in enhancing safety by detecting unauthorized movement within vehicles or transport facilities.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

The RTD Module is a precise solution for temperature measurement using RTD (Resistance Temperature Detector) probes. Equipped with an advanced RTD converter, this module seamlessly reads and interprets data from 2-pin, 3-pin, or 4-pin RTD probes, ensuring accurate temperature monitoring across various applications. Whether used in industrial process control, HVAC systems, or scientific research, the RTD Module provides reliable and detailed temperature readings, supporting various RTD configurations.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

The NFC Broker Module is a versatile solution that functions as an NFC reader, writer, and emulator. This adaptability allows seamless interactions with various NFC tags and devices. Its adaptive frequency tuning circuit ensures precise and error-free operations, even in challenging environments like under displays, maintaining optimal performance. Whether for use in contactless payment systems, secure access control, data exchange applications, or smart devices, the NFC Broker Module delivers unmatched reliability and efficiency, enhancing the capabilities of your NFC-enabled solutions.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

The M.2 CAT-M NB-IoT Module is a cutting-edge communication solution in a compact M.2 form factor, supporting CAT-M and NB-IoT connectivity plus GNSS positioning. This module offers reliable cellular connectivity and precise geolocation capabilities, making it ideal for many IoT applications, including smart metering, asset tracking, and remote monitoring. The module's support for CAT-M and NB-IoT ensures efficient wide-area network communication, while the integrated GNSS provides accurate positioning.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

Even though Evolve comes pre-programmed, reprogramming it with custom firmware is possible. This document describes reprogramming the microcontroller in three steps.

Prerequisites

This versatile Hall-effect sensor, designed to enhance security and environmental analysis capabilities, integrates multiple sensing functionalities. These include temperature, humidity, pressure, ambient light, and infrared light readings. Primarily engineered to detect door or window openings, this module plays a critical role in security applications by instantly identifying unauthorized access. Furthermore, in pair with temperature and humidity measurements, the onboard pressure sensor accurately detects window breaks, providing an added layer of security and environmental monitoring. Most importantly, when integrated into intelligent security systems, this sensor add-on ensures comprehensive situational awareness, instilling a sense of security and enhancing the safety of your premises.

This sensor module measures highly accurate CO2, relative humidity, and temperature. CO2 is a crucial indicator of indoor air quality (IAQ), as high levels compromise humans' cognitive performance and well-being. This module is compatible with relevant IAQ standards and has a high-accuracy measurement range of 400 – 5.000 ppm.

Sensor Module

Sensirion SCD41 CO2 and RH&T Sensor

SCD41 is Sensirion's next-generation miniature CO2 sensor. It builds on the photoacoustic NDIR sensing principle and Sensirion's patented PASens® and CMOSens® technology to offer high-accuracy CO2 readings and relative humidity and temperature measurements.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

Most sensors came with factory calibration data embedded. Evolve's firmware reads the factory calibration data to provide accurate sensor readings. Some sensors, due to their nature, need to be calibrated periodically. This document describes entering calibration mode and resetting the calibration data to the factory settings.

Prerequisites

• Evolve with all the sensors attached.

The Irradiance Module is a precision tool designed to optimize solar panel performance through detailed efficiency analysis. This module reads the current generated by a small reference solar panel and calculates the efficiency of a larger panel by extrapolating the data. Additionally, it measures the temperature of the reference solar panel to accurately calculate the power output in watts and determine the solar radiance. Ideal for applications in solar energy research, photovoltaic system monitoring, and renewable energy optimization, the Irradiance Module empowers users to fine-tune their solar installations, ensuring maximum energy harvest and efficiency.

Evolve is a highly customizable, compact, energy-efficient data collection solution. It features modular sensor ports for customizing the device to specific measurement needs and an M.2 connectivity port for flexible connectivity options. In addition, the device can be powered by various sources, such as industrial batteries or a solar panel, making it a versatile choice for remote sensing applications.

Technical Specifications

The following table outlines the capabilities of the device.

Compatible Sensor Modules

Evolve is compatible with the following sensor modules.

Compatible Connectivity Modules

The following connectivity options work with Evolve.

Communication Protocols

Evolve's stock firmware supports the following communication protocols. You can develop custom firmware to add more.

Physical Properties

This table shows the mechanical properties of the device.

Environmental Conditions

Environmental Conditions refer to the physical and atmospheric conditions surrounding the device.

Electrical Characteristics

This table indicates the electrical specifications of the device.

Connectivity Options

This table lists the communication options of the device.

Pin Description

This table explains the function and electrical characteristics of each pin or terminal on the device.

Libraries and Samples

Some of our devices come with firmware that automatically utilizes the module without requiring any coding. For development kits or further customization, you may choose to use the following libraries and samples to create a custom application.

This device measures the depth or distance of an object, liquid, or snow. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

Technical Specifications

The following table outlines the capabilities of the device.

Sensing Specifications

The following table shows sensor characteristics.

Physical Properties

This table shows the mechanical properties of the device.

Environmental Conditions

Environmental Conditions refer to the physical and atmospheric conditions surrounding the device.

Electrical Characteristics

This table indicates the electrical specifications of the device.

Absolute Maximum Ratings

Absolute maximum ratings indicate the maximum electrical or environmental parameters this device can withstand without damage.

Connectivity Options

This table lists the communication options of the device.

Communication Protocols

This device supports the following communication protocols.

This device measures the precipitating rain using the tipping bucket mechanism. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

Technical Specifications

The following table outlines the capabilities of the device.

Sensing Specifications

The following table shows sensor characteristics.

Physical Properties

This table shows the mechanical properties of the device.

Environmental Conditions

Environmental Conditions refer to the physical and atmospheric conditions surrounding the device.

Electrical Characteristics

This table indicates the electrical specifications of the device.

Absolute Maximum Ratings

Absolute maximum ratings indicate the maximum electrical or environmental parameters this device can withstand without damage.

Connectivity Options

This table lists the communication options of the device.

Communication Protocols

This device supports the following communication protocols.

This device communicates using the Modbus RTU protocol over the RS-485 standard.

Device Address

This device's preconfigured user-definable address is 0x13. Users can change the address using the holding registers.

Modbus Function Codes

The following Modbus function codes are functional with this device.

Device Registers

The following registers are available with this device.

Communication Syntax

Reading sensor data

The host device can read one or more sensor data by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x04) [1 Byte] + Input register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x04) [1 Byte] + Response register length in Bytes [1 Byte] + Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Reading configuration register

The host device can read one or more configuration registers by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x03) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x03) [1 Byte] + Response register length in Bytes [1 Byte], Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing single configuration register

The host device can write one configuration register.

Command from the host: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [2 Bytes MSB first] + Value to be set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [1 Byte] + Value set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing multiple configuration registers

The host device can write multiple configuration registers.

Command from the host: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes] + Configuration values length in Bytes [1 Byte] + Value to be set 1 [2 Bytes MSB first] + Value to be set N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [1 Byte], Value set [2 Bytes MSB first], CRC [2 Bytes MSB first]

The sensor array can measure different environmental factors like climate, noise, ambient light, and even different smells using AI on the edge. It can also control IR devices such as air-conditioners. This combination offers flexibility and cost-effectiveness for monitoring multiple environmental conditions in various applications, including intelligent buildings, agriculture, and industrial process control.

Sensor Array

This device measures temperature, relative humidity, and pressure. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

This device measures sunlight's irradiance in the manner of solar panels. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

This device measures wind speed and direction using an anemometer and wind direction arrow. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

This device measures wind speed and direction using ultrasonic waves. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

Installation

Installation guidelines are coming soon.

Library Overview

This device communicates using the Modbus RTU protocol over the RS-485 standard.

Device Address

This device's preconfigured user-definable address is 0x14. Users can change the address using the holding registers.

Modbus Function Codes

The following Modbus function codes are functional with this device.

Device Registers

The following registers are available with this device.

Communication Syntax

Reading sensor data

The host device can read one or more sensor data by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x04) [1 Byte] + Input register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x04) [1 Byte] + Response register length in Bytes [1 Byte] + Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Reading configuration register

The host device can read one or more configuration registers by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x03) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x03) [1 Byte] + Response register length in Bytes [1 Byte], Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing single configuration register

The host device can write one configuration register.

Command from the host: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [2 Bytes MSB first] + Value to be set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [1 Byte] + Value set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing multiple configuration registers

The host device can write multiple configuration registers.

Command from the host: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes] + Configuration values length in Bytes [1 Byte] + Value to be set 1 [2 Bytes MSB first] + Value to be set N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [1 Byte], Value set [2 Bytes MSB first], CRC [2 Bytes MSB first]

This device communicates using the Modbus RTU protocol over the RS-485 standard.

Device Address

This device's preconfigured user-definable address is 0x11. Users can change the address using the holding registers.

Modbus Function Codes

The following Modbus function codes are functional with this device.

Device Registers

The following registers are available with this device.

Communication Syntax

Reading sensor data

The host device can read one or more sensor data by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x04) [1 Byte] + Input register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x04) [1 Byte] + Response register length in Bytes [1 Byte] + Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Reading configuration register

The host device can read one or more configuration registers by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x03) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x03) [1 Byte] + Response register length in Bytes [1 Byte], Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing single configuration register

The host device can write one configuration register.

Command from the host: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [2 Bytes MSB first] + Value to be set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [1 Byte] + Value set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing multiple configuration registers

The host device can write multiple configuration registers.

Command from the host: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes] + Configuration values length in Bytes [1 Byte] + Value to be set 1 [2 Bytes MSB first] + Value to be set N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [1 Byte], Value set [2 Bytes MSB first], CRC [2 Bytes MSB first]

This device measures soil temperature, EC (Electrical Conductivity), and moisture. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

Technical Specifications

The following table outlines the capabilities of the device.

Sensing Specifications

The following table shows sensor characteristics.

Physical Properties

This table shows the mechanical properties of the device.

Environmental Conditions

Environmental Conditions refer to the physical and atmospheric conditions surrounding the device.

Electrical Characteristics

This table indicates the electrical specifications of the device.

Absolute Maximum Ratings

Absolute maximum ratings indicate the maximum electrical or environmental parameters this device can withstand without damage.

Connectivity Options

This table lists the communication options of the device.

Communication Protocols

This device supports the following communication protocols.

This device communicates using the Modbus RTU protocol over the RS-485 standard.

Device Address

This device's preconfigured user-definable address is 0x12. Users can change the address using the holding registers.

Modbus Function Codes

The following Modbus function codes are functional with this device.

Device Registers

The following registers are available with this device.

Communication Syntax

Reading sensor data

The host device can read one or more sensor data by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x04) [1 Byte] + Input register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x04) [1 Byte] + Response register length in Bytes [1 Byte] + Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Reading configuration register

The host device can read one or more configuration registers by calling the starting register address.

Request from the host: Device address [1 Byte] + Function code (0x03) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x03) [1 Byte] + Response register length in Bytes [1 Byte], Register 1 [2 Bytes MSB first] + Register N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing single configuration register

The host device can write one configuration register.

Command from the host: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [2 Bytes MSB first] + Value to be set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x06) [1 Byte] + Holding register address [1 Byte] + Value set [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Writing multiple configuration registers

The host device can write multiple configuration registers.

Command from the host: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [2 Bytes MSB first] + Requested register length [2 Bytes] + Configuration values length in Bytes [1 Byte] + Value to be set 1 [2 Bytes MSB first] + Value to be set N [2 Bytes MSB first] + CRC [2 Bytes MSB first]

Response from the device: Device address [1 Byte] + Function code (0x10) [1 Byte] + Holding register start address [1 Byte], Value set [2 Bytes MSB first], CRC [2 Bytes MSB first]

This device measures VOC, NOx, CO2, PM (Particulate Matter), relative humidity, and temperature. It transmits data using Modbus RTU communication protocol over the RS-485 standard.

This device communicates using the Modbus RTU protocol over the RS-485 standard.

Device Address

This device's preconfigured user-definable address is 0x17. Users can change the address using the holding registers.