MC33912_10 Datasheet, PDF (79/94 Pages) Freescale Semiconductor, Inc – LIN System Basis Chip with DC Motor Pre-driver and Current Sense

MC33912BAC / MC34912BAC
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 node.
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 during
external disturbance.
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 42. LIN Interface
Slew Rate Selection
The slew rate can be selected for optimized operation at
10.4 and 20 kBit/s as well as a fast baud rate for test and
programming. The slew rate can be adapted with the bits
LSR 1:0 in the LIN Control Register (LINCR). The initial slew
rate is optimized for 20 kBit/s.
LIN Pull-up Disable In Stop And Sleep Modes
In cases of a LIN bus short to GND 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
Mode Control Register (MCR). The LINPE bit also changes
the Bus wake-up threshold (V_BUSWU).
This feature will reduce the current consumption in STOP
and SLEEP modes. It also improves performance and safe
operation.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33912
79