The main module of the HomeLab is a controller development board (controller board) equipped with a new generation of Atmel ATxmega128A1U USB-enabled microcontroller. In addition to the microcontroller, the board consists of several peripherals, voltage stabilizer, connectors, SD memory card slot. The controller board has the following features:
The module is equipped with a LDO voltage stabilizer (with low dropout). The module can be powered with a step down transformer with an output voltage which is greater than 6 volts and lower than 14 volts. In order to reduce power losses it is recommended to use power supply between 6-9V. The power LED signalizes a connected feed. The power LED must be lit, when connecting to the power. If it does not illuminate, the cause may be an inadequate power supply or a short circuited Controller module or a short circuit in other connected devices. Controller is equipped with fuses. If overcurrent occurs, the fuse blow and protect the most expensive components. Fuses can be changed, but it is recommended to do an experienced electronics experts. Fuses are small SMD components, and the user is difficult to replace them. The microcontroller can be programmed over USB, through the bootloader. To enter the bootloader, press and hold the button S0 on the Controller module, and then reset the controller.
The Controller module is equipped with a status LED, which is connected to the microcontroller pin PQ2. The status LED will light up, if the pin is set to low (logical 0). It is good to use as a simple indicator. Another LED is connected to the pin PQ0, but it is reserved for the USB connection, and the programmatic management is not recommended. Pin PQ1 is connected through the voltage divider to USB power. This pin can be used to read, if the USB cable is connected to the Controller module or not. The module is equipped with SD memory card slot, where it can be used as a standard microSD memory card. The memory card is connected to the microcontroller via the ISP interface and can be used to store data where data must be maintained even if the power supply is removed.
When connecting the controller module with other modules or devices, you must first make sure that the controller module power supply is not connected. Modules and devices must be connected to each other with care. It is important not to use excessive force, wrong handling may damage the module. For programming and to power with low currency (less than 500mA) you must only connect the controller module with a PC using an USB port. If you are using modules that need to use a greater current than 500 mA, you must use a separate power source. If a controller module is connected to a separate power source, then the module automatically does not use USB a power supply.