This project mission is to build an expansion board for Raspberry Pi 2 (or 3), endowing it with a set of Input/Output features and adapt a real-time executive compatible with the expansion. The I/O features should be compatible with PiFace Digital 2 and extentions should be provided to existing software as drivers for using aditional I/O devices mentioned on the material section.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The hardware is going to be developed on Altium: PCB Design Software, and the board is going to be manufactured with surface-mount technology (SMT) at Instituto Superior Técnico-TagusPark facilities. The real-time executive will be implemented in FreeRTOS, which is a real time operative system that's free and solely owned, developed and maintained by Real Time Engineers Ltd.

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Why FreeRTOS?

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Technical summary:

• Prioritised scheduling:

  • Pre-emptive option, time slicing option;

  • Co-operative option;

• Tickless mode for low power;

• Fast direct to task notifications;

• Excellent and extensible execution trace capability;

• Multiple kernel aware IDE plug-ins;

• Flexible and easy to use queues;

• Binary, counting and recursive semaphore;

• Mutex with priority inheritance;

• Event groups and flags;

• Software timers;

• Stack overflow detection;

• Selection of memory allocation schemes;

• Many ports never completely disable interrupts;

• No ports perform non-deterministic operations with interrupts disabled.

 

The board should be able to control a SUBA (RC Car) equipped with various sensors, to follow a test track with climbs and descents. In addition to the engine and steering servo, the tilt sensor should also be read, and actuating on existing LED's.

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