Gateway device overcomes LIN bus limitations
Global microelectronics engineering company, Melexis, has announced a new LIN-to-LIN gateway that overcomes the limitation of just 16 devices on a typical LIN bus. Each MLX81120 connects as a LIN slave on the main LIN bus and is controlled directly from the vehicle's Body Control Module (BCM). The new device allows for up to 16 LIN RGB slave modules on a private LIN bus, thereby permitting up to 196 LED lighting devices to be connected to a single BCM via a LIN bus.
The fully featured, second generation, LIN-to-LIN gateway is based upon the popular MLX16 RISC CPU application controller. The 16-bit MCU includes 32kB Flash (with ECC), 16kB ROM, 2kB RAM and a 380b EEPROM (with ECC). The ROM comes pre-loaded with a LIN driver, bootloader, math library and an RGB colour mix algorithm.
The LIN slave protocol controller operated up to 19.2kBaud and is compliant with LIN 2.x and SAE J2602. This block processes frames autonomously; ensuring that there are very few interrupts to the main application. Also included in the MLX81120 are a master and slave LIN transceiver, both of which are also compliant with LIN 2.x and SAE J2602. The 2nd master transceiver enables a decentralised ambient lighting architecture within a car, which makes it possible to easily add and/or change lighting functions for different car models or equipment options without changing the complex body control module or light ECU.
Extensive I/O capability is built in including four high voltage I/O lines, 16-bit PWM outputs, interrupt capable inputs and a 10-bit ADC with an integrated pre-driver. The MLX81120 has a highly efficient voltage regulator that consumes just 20μA in sleep mode. Other features include LED temperature compensation, LED leakage compensation / control and an integral battery and temperature monitor.
The flexible and configurable MLX81120 can be configured to meet customer needs via the flash memory and requires only three external components for LIN RGB, thereby saving board space and reducing the solution cost.
Michael Bender, Product Line Manager Lighting for Melexis commented: "Automotive is a core market for Melexis. As lighting solutions proliferate, especially within the cabin designers have told us they need a simple way to overcome the architectural limits of the LIN bus. The new MLX81120 does exactly that, allowing lighting bus segmentation and extension for future use cases. Furthermore, the device reduces the board space (and cost) significantly, while providing many useful features and protections. For example, even by adding extensive lighting functionalities the existing body control module can be kept as simple as possible."
Offering an automotive temperature range of -40 to 125°C and housed in a small DFN4x4 12-pin package the MLX81120 is available as PPAP samples, along with a useful demo board and development software.