USB-LIN
This topic describes the USB-LIN hardware.
USB-8476/USB-8476s: LIN
The USB-LIN physical layer circuitry interfaces the LIN microcontroller to the physical bus wires. The USB-LIN physical layer is powered externally from VBat (required for the LIN bus), and is optically isolated up to 500 VDC (withstand, 2s max) channel-to-bus. This isolation protects your NI-LIN hardware and the PC it is connected to from being damaged by high-voltage spikes on the LIN bus.
Transceiver
USB-LIN hardware uses the Atmel ATA6620 LIN transceiver. The ATA6620 is fully compatible with the ISO-9141 standard and supports baud rates up to 20 kbps. This device also supports advanced power management through a low-power sleep mode. This feature is provided as the Transceiver Mode attribute of the Frame API. For detailed ATA6620 specifications, refer to the Atmel ATA6620 data sheet.
Bus Power Requirements
The LIN physical layer is powered through the LIN bus VBat power. The USB-8476 physical layer requires a DC power supply with an output of 8 to 18 V, as specified in Table 3-10, Bus Power Requirements for USB-8476. You should take these requirements into account when determining the bus power supply requirements for the system. The Gnd pin serves as the reference ground for the isolated signals. Refer to USB-LIN Connector Pinout for information about how to connect signals to a LIN interface.
| Characteristic | Specification |
|---|---|
| Voltage | 8-18 VDC on VBat connector pin (referenced to Gnd) |
| Current | 55 mA maximum |
LED Indicators
The following table provides a description of the LEDs on the front panel of the USB-8476 and USB-8476s.
| Name | Function |
|---|---|
| USB | Indicates connectivity to a USB Host. Green indicates a USB full speed connection. Amber indicates a USB high speed connection. |
| CAN | Flashes to indicate the presence of traffic on the CAN bus. |
| VBAT | Indicates the presence of LIN bus power. |