PRELIMINARY TESTS¶

In order to get in touch with the equipment, a series of simple tests were carried out, à la “hello world”. These tests were carried out on the Development Board, taking advantage of the documentation and sample software provided by the manufacturer. After reading the documentation concerning the DB, the MCU and the operating system, we proceeded with the testing.

The first test, was carried out to check the programmer and the provided OS (Salvo RTOS). The program, consisted of a output pin switching every 5 seconds, from which a LED was connected. The test was successful.

Diagram showing the operation of the test program.

The next test, was aimed to check the communication between a PC and the MCU. Using the same task repeated every 5 seconds, a message with a baudrate of 9600 was sent through the UART connected to the USB (through the FTDI chip). The messages were successfully received on a PC.

Connections diagram.

Finally, a test was made to check the operation of the RF transmitter. To accomplish such task, the transmitter was connected to the MCU through the same UART used in the previous test. Lacking an appropriate receiver capable of demodulating the message, the checking was made measuring the signal at the antenna output pin with an oscilloscope, and measuring the emitted power with a spectrum analyzer. The results showed that power was being transmitted in the frequencies corresponding to a logic 0 and logic 1, so the test was considered successful.

Diagram of signals measured at the output of the UART and the output of the transmitter.

At the end of this series of tests, the familiarization with the equipment was deemed completed, so the mission analysis stage was started. Further testing is expected to be done when the final prototype is developed.