33910 Datasheet, PDF (29/44 Pages) Freescale Semiconductor, Inc – LIN System Basis Chip with 2x60mA High Side Drivers

FUNCTIONAL DEVICE OPERATIONS
OPERATIONAL MODES
LIN PHYSICAL LAYER
The LIN bus pin provides a physical layer for single-wire
communication in automotive applications. The LIN physical
layer is designed to meet the LIN physical layer specification
and has the following features:
• LIN physical layer 2.0 compliant
• Slew rate selection
• Over-current shutdown
• Over-temperature shutdown
• LIN pull-up disable in Stop and Sleep Modes
• Advanced diagnostics
• LIN dominant voltage level selection
The LIN driver is a low side MOSFET with over-current
and thermal shutdown. An internal pull-up resistor with a
serial diode structure is integrated, so no external pull-up
components are required for the application in a Slave Mode.
The fall time from dominant to recessive and the rise time
from recessive to dominant is controlled. The symmetry
between both slopes is guaranteed.
LIN Pin
The LIN pin offers a high susceptibility immunity level from
external disturbance, guaranteeing communication.
INTERRUPT
CONTROL
MODULE
WAKE-UP
MODULE
High-voltage
Shutdown
High Side
Interrupt
LIN
Wake-up
MOD1:2
LSR0:1
LINPE
LDVS
RXONLY
RXSHORT
TXDOM
LINOT
LINOC
VS1
LIN – DRIVER
Slope and Slew Rate Control
Over-current Shutdown (interrupt maskable)
Over-temperature Shutdown (interrupt maskable)
30K
LIN
TXD
WAKE-UP
FILTER
SLOPE
CONTROL
LGND
RXD
RECEIVER
Figure 18. LIN Interface
Slew Rate Selection
The slew rate can be selected for optimized operation at
10.4 and 20kBit/s as well as a fast baud rate for test and
programming. The slew rate can be adapted with the bits
LSR1:0 in the LIN control register (LINCR). The initial slew
rate is optimized for 20kBit/s.
LIN Pull-up Disable In Stop and Sleep Mode
To improve performance and for safe behavior in case of
LIN bus short to ground or LIN bus leakage during Low Power
Mode the internal pull-up resistor on the LIN pin can be
disconnected by clearing the LINPE bit in the MCR. The bit
LINPE also changes the bus wake-up threshold (V_BUSWU).
In case of a LIN bus short to GND, this feature will reduce
the current consumption in Stop and Sleep modes.
Over-Current Shutdown (LIN Interrupt)
The output low side FET is protected against over-current
conditions. In case of an over-current condition (e.g. LIN bus
Analog Integrated Circuit Device Data
Freescale Semiconductor
33910
29