LED test with two temperature calibration and EEPROM flashing

LED test with two temperature calibration and EEPROM flashing. This thesis project addresses a modern challenge in testing automotive boards under harsh conditions, such as temperatures 40 degrees higher than the ambient environment. The challenge arises from the necessity for companies to evaluate the expected behavior of their products under all possible operating conditions, especially in the automotive sector. To achieve this, Spea, one of the leading companies in testing, was involved in carrying out this challenging project. The device under test (DUT) is an electronic board in which there are mounted two microprocessors, 14 RGB LEDs and other minor components with the aim of lightning on the dashboard of a car. In particular there is one master processor that receives the commands from the main CPU of the car through CAN-FD communication and a slave processor that is in charge of driving the LEDs by means of MeLiBu interface. The first step of the project was the fixture generation, that consists on the development of the customizable adapter used in the Spea 3030 system to test pallets of boards. This work didn't require the use of the system because the test was performed on bench on a single board, anyway this step was useful to study the components and to add the access points (test points) to program the microprocessors. After fixture generation, the microprocessors were flashed to program them and verify their correct functionality. To achieve this, the On-Board Programming (OBP) team at Spea developed two drivers to write and read the ROM and EEPROM memories of the controllers. To enable communication, all necessary physical connections were implemented between the respective board test points and the YADIO, a digital input/output board used for OBP. Once the correct functioning of the processors was verified, the most challenging part of the project was sending the correct CAN-FD commands to turn on the LEDs. This was accomplished using a Visual Basic program and a Vector CAN, which created a CAN-FD interface between the PC and the board. After several attempts, the commands were successfully sent, and the LEDs illuminated with white light. At this stage, under normal conditions, the light saturation and intensity values were measured using an LCS probe, a SPEA system capable of measuring all LED parameters and easily connecting to a PC via USB. The values for all 14 LEDs were used in a formula provided by the customer to calculate the calibration parameter, which was then written into the EEPROM memory of the microprocessor. These steps were then repeated in a different environment, at a temperature 40 degrees higher. To simulate this condition, with the assistance of the mechanical team at Spea, an heating buffer was developed to house the board and bring it to the desired temperature. The buffer consisted of a first layer of aluminum, which efficiently distributed heat across the surface, and a second thin layer of vetronite, which provided electrical insulation to prevent short circuits with the DUT. Once the environment was stabilized, the light parameters were recalculated and written again into the EEPROM memory of the microprocessor. In conclusion, this thesis successfully established a comprehensive testing methodology for automotive LED boards under harsh temperature conditions, paving the way for further enhancements, such as testing with different light colors and intensities.