FUNCTIONAL DESCRIPTION
INTRODUCTION
FUNCTIONAL DESCRIPTION
INTRODUCTION
The System Basis Chip (SBC) is an integrated circuit
dedicated to car body applications. It includes three main
blocks:
1. A dual voltage regulator
2. Reset, watchdog, wake-up inputs, cyclic wake-up
3. CAN low speed fault tolerant physical interface
Supplies
Two low drop regulators and one switch to V
BAT
are
provided to supply the
ECU
microcontroller or peripherals,
with independent control and monitoring through SPI.
FUNCTIONAL PIN DESCRIPTION
TRANSMIT AND RECEIVE DATA (TX AND RX)
The RX and TX pins (receive data and transmit data pins,
respectively) are connected to a microcontroller’s CAN
protocol handler. TX is an input and controls the CANH and
CANL line state (dominant when TX is LOW, recessive when
TX is HIGH). RX is an output and reports the bus state.
MASTER OUT/ SLAVE IN (MOSI)
MOSI is the Master Out Slave In pin of the serial peripheral
interface. Control data from a microcontroller is received
through this pin.
SYSTEM CLOCK (SCLK)
This pin clocks the internal shift registers for SPI
communication.
VOLTAGE REGULATOR ONE AND TWO
(V1 AND V2)
The V1 pin is a 3% low drop voltage regulator dedicated to
the microcontroller supply (nominal 5V supply).
The V2 pin is a low drop voltage regulator dedicated to the
peripherals supply (nominal 5V supply).
CHIP SELECT (CS)
CS is the Chip Select pin of the serial peripheral interface
(SPI). When this pin is LOW, the SPI port of the device is
selected.
RESET (RST)
The RST (reset) pin is an input/output pin. The typical
reset duration from SBC to microcontroller is 1ms. If longer
times are required, an external capacitor can be used. SBC
provides two RST output pull-up currents. A typical 30µA pull
up when Vreset is below 2.5V and a 300uA pull up when
reset voltage is higher than 2.5V. RST is also an input for the
SBC. It means the MC33389 is forced to Normal Request
mode after RST is released by the microcontroller
LEVEL 0-2 INPUTS (L0: L2)
The L0: L2 pins can be connected to contact switches or
the output of other ICs for external inputs. The input states
can be read by the SPI. These inputs can be used as wake-
up events for the SBC.
NO CONNECT (NC)
No pin connection.
INTERRUPT (INT)
The Interrupt pin INT is an output that is set LOW when an
interrupt occurs. INT is enabled using the Interrupt Register
(INTR). When an interrupt occurs, INT stays LOW until the
interrupt source is cleared.
INT output also reports a wake-up event.
TERMINATION RESISTANCE (HIGH AND LOW?)
(RTH AND RTL)
External CAN bus high and low termination resistance pins
are connected to these pins.
CAN HIGH AND CAN LOW OUTPUTS
(CANH AND CANL)
The CAN High and CAN Low pins are the interfaces to the
CAN bus lines. They are controlled by TX input level, and the
state of CANH and CANL is reported through RX output.
GROUND (GND)
This pin is the ground of the integrated circuit.
MASTER IN/ SLAVE OUT (MISO)
MISO is the Master In Slave Out pin of the serial peripheral
interface. Data is sent from the SBC to the microcontroller
through the MISO pin.
VOLTAGE BATTERY (VBAT)
This pin is the voltage supply from the battery.
VOLTAGE REGULATOR THREE (V3)
This pin is a 10
Ω
switch to VBAT, which is used to supply
external contacts or relays.
33389
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
