Car cabin lighting is developing towards intelligent direction, through RGB LED controls can make the interior lighting to achieve more cool effect, increase personalized driving experience. In addition, the combination of intelligent cabin lighting system and ADAS auxiliary driving system can also play a warning role for drivers and improve the safety of driving. However, with the increasing number of in-car LED applications, traditional solutions using external LED driver chips are also facing great design challenges.
In this case, the emergence of Microchip ISELED technology has solved the problem well. The basic idea of ISELED is that parameters that originally required processing by external processors, such as brightness and color stability, were transferred to RGB leds themselves, so that leds can be "digitized," so that they can be addressed via a "streamlined" communication protocol, in which control is realized only by reading target parameters representing color and brightness.
DSPIC33CK, a high-performance digital signal controller (DSC) of Microchip, seems to have brought about low cost and simpler design requirements for ISELED automotive atmosphere lamps. Its built-in CIP modules (SPI, DMA, CRC, 5V I/O) are used to realize hardware-based ISELED agreements, thus minimizing software intervention. An independent SPI that supports 5-bit hardware mode and a flexible CRC engine simplified frame creation of ISELED.
DMA seems to have increased the throughput of ISELED, so complex animation and lighting effects can be realized with the help of this scheme. The 5V I/O allows direct connection of ISELED without any adhesive logic or external level converters, greatly reducing system risks. In addition, the DSPIC33CK also supports CAN-FD and LIN communication as well as robust waterproof capacitive touch sensors, enabling the integration of advanced features such as HMI Touch.
The automobile atmosphere lights program of the Microchip DSPIC33CK256MP508-IPT development platform, which supports ISELED agreement, may reduce the complicated design challenges of automobile interior atmosphere lights, allowing users to design more intelligent product applications at low cost. The development boards of DSPIC33CK, ISELED interface boards, and ISELED eled boards, seem to simplify the design requirements of SELED automobile atmosphere lamps, and reduce the input of design costs.
Through this scheme, a maximum of 4079 LED can be connected in series in a single channel, and the color brightness of each LED can be independently controlled, which can simplify the relationship between MCU, driver chip and LED, greatly reduce the workload of external MCU, and further avoid the disadvantages of external LED driver scheme.
Core technical advantages:
● Microchip's solutions provide an 8-bit, 16-bit to 32-bit MCU, all of which support ISELED, and users choose the most cost-effective programs according to the actual application needs.
● Can integrate HMI touch function, security function and communication function and add dynamic lighting effect;
● MPLAB code configurator, a graphical development interface of ISELED CIP, an ISELED program is easily embedded into the target applications.
● Use differential serial communication protocol, half duplex communication, support LED self-diagnosis, simple wiring, EMC performance is excellent;
● LED built-in driver chip, factory has been calibrated, ready to use.
Project specification:
● A single channel can be connected to 4079 LED, each LED color brightness can be independently controlled;
● 2Mbps data transmission rate, high-speed refresh;
● Differential half duplex communication, support LED self-diagnosis;
● Support functional safety, support CAN-FD;
● Built-in CIP module (SPI DMA CRC 5V I/O) can simplify the hardware design, can realize touch key control.
