Armadeus small processor boards
The Armadeus board has two big connectors (Hirose 120 pin FX8) and need to be plugged on a main board through these two connectors to communicate with the outside world, and more simply, with electrical power. Armadeus developed a few development boards. They include lots of input/output capabilities, power management, and so on.
For our goal, we need to develop a new main board, with a reduced size and weight compared to the Armadeus' development board, and with only the needed external connectors and components. On this page, we make the list of those needed connectors and design constraints.
The dev board embeds three converters and regulators, for 1.8V, 3.3V and 5V.
The RTC device is used to keep track of the time in case of power interruption or reboot. The processor board embeds one, but it is not saved in case of power interruption. Consequently, the DevFull board from Armadeus embeds another one, the Maxim DS1374 with a battery. It uses the I²C bus and has an internal temperature-compensated oscillator. Datasheet is uploaded here.
For our main board, we only need the battery, since the main board and the processor board should not be decoupled. Using a GPS would be a benefit since it provides accurate time. Else, upload telemetry has to be setup to allow time setting from the outside of the system, when the board is plugged to the main board. If this is too boring, putting a RTC on the main board, as Armadeus does, can be considered.
We might need an SD card for massive storage of sensor and flight information. The default is 256MB on the APF27 processor board.
An ADC may be needed if analogic sensors are used. On the Armadeus DevFull board, they use the MAX1027 component.
Camera modules can't be directly connected to APF signals, but need a breakout board. Moreover, since they need to be put in a different place than the processing board, they need a connector on the main board.
FPGA connectors for servo PWM
If we chose servo as the actuators for the airplane ailerons, we will need a PWM signal to control them. The FPGA of Armadeus boards is able to control lots of them as explained here, but we need to add the connectors to the main board.