Power Board for the Mercury System

The set of boards that make up the Mercury System is organised into the following “families”:

• Base Board (BB): This is the “brain” of the whole Mercury System and contains the main logic unit, several communication buses and the connectors for interfacing the slaves. It also contains a simple power supply and a charging unit for a single LiPo cell (enough to meet the power requirements of simpler systems). It can exist in several variants, depending on the microcontroller unit used.

• Modem Board (MB): this is the board that provides network connectivity. It can exist in several variants, depending on the network interface (GSM / GPRS, Wi-Fi, BT, Radio …). It is interfaced to the base board over a dedicated serial line.

• Power Board (PB): this is the board that meets the particular energy needs of the system, whenever that is necessary. They can vary according to the particular energy need to be met (high power, solar harvesting, piezoelectric harvesting, and so on).

• Slave Board (SB): these are the peripherals of the system and vary according to the specific sensor or actuator fitted. Typical examples are SBs with relays, temperature sensors, RGB LED controllers, servo controllers, accelerometers, and so on. They communicate with the BB over I2C or UART and a dedicated command set.

• Expansion Board (EB): these are the boards that allow the Mercury boards to be connected side by side. There are variants that can carry displays, a battery holder, and so on.

• Brain-Less Board (BL): these are the boards without a controller. In general they carry really simple sensors or actuators that do not need the bus interface. They are an alternative to the slave boards for applications that have to keep costs down.

The Slave Boards and the Modem Boards come pre-programmed with firmware that implements a dedicated command set for high-level control, while the Base Boards carry a software framework that provides all the low-level services (operating system, peripheral drivers, system services, and so on), leaving the user with only the application-level logic to develop.

HAL (Hardware Abstraction Layer): the purpose of this layer is to hide the hardware dependencies from the layers above.
SML (System Management Layer): the purpose of this layer is to provide services for managing the communication buses (I2C, UART) and for managing the Modem Board (WiFi, BT, GSM / GPRS). It also provides a set of system services, such as System Power Management, RTCC, USB terminal, and so on.
It is divided into two main components:

OSL (Operative System Layer): this layer consists of a lightweight RTOS that provides the basic services to the system, such as the scheduling tables for the various tasks, events, SW timers, alarms, and so on.

There are several sub-families of Slave Board:

• Sensor Slave Board
• Actuator Slave Board
• Communication Slave Board
• Interface Slave Board
• Special Slave Boards

The table below gives a few examples for each sub-family:

• Mercury System Getting Started Guide IoT and Connectivity Made Simple
• Mercury Framework
• Framework User Manual
• MS_PB110_Schematic