Simplify Switch Application Design with LIN Bus Connections

By Daniel Yordanov and Berthold Gruber

Low-cost local interconnect networking (LIN) systems are typically used in comfort, powertrain, sensor and actuator automotive applications. As the number of applications and control switches to manage them has increased and the market for LIN systems has grown, so has the need for greater system efficiency, tighter integration and lower costs. In addition, applications for which the switches are located far from the control electronics and wires integrated into the wiring harness require high-voltage (HV) switches. Atmel supports these applications with a modular LIN family, including simple transceiver ICs, complex system basis chips (SBCs) and system-in-a-package (SiP) solutions. The Atmel® ATA6642 SiP device, in particular, was designed for complete LIN bus node applications.

The ATA6642 provides benefits for LIN applications such as the following:

• Switch control: Eight HV I/O ports allow flexible control of up to eight single switches, including flexible switch monitoring. Each input can be configured to trigger an interrupt upon state change, and if a state change is detected, an interrupt request is generated. If no wake-up occurs on a switch, the current source can be disabled in the serial peripheral interface (SPI) configuration register.
• Voltage measurement: The device’s HV I/O ports are each equipped with a voltage divider. The VDIV pin guarantees a voltage- and temperature-stable output ratio for the selected input.
• Pulse-width-modulated (PWM) load control: The device’s switch interface current sources can directly control PWM loads, such as switch scanning and LED driving. A universal serial interface (USI) helps enable significantly higher transfer rates and uses less code space than solely software-based solutions. Interrupts are included to reduce the processor load.
• RGB LED control: With its constant current sources, the device is well suited for LED control systems: for example, to control an RGB LED.
• H-bridge relay control: The device can be used as a relay driver: for example, in a window lifter system. If the output current of each I/O port is not sufficient to drive the load, the output pins can be interconnected to achieve a higher load current.

For diagrams and more details about the Atmel ATA6642 and its use in LIN applications, see the article “Simplifying the Design of Switch Applications with LIN Bus Connections.”