MC33996 查看數據表（PDF） - Motorola => Freescale
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MC33996 Datasheet PDF : 16 Pages
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Freescale Semiconductor, Inc.
SYSTEM/APPLICATION INFORMATION
INTRODUCTION
The 33996 is designed and developed for automotive and
industrial applications. It is a 16-output power switch having
24-bit serial control. The 33996 incorporates SMARTMOS
technology having CMOS logic, bipolar/MOS analog circuitry,
and independent DMOS power output transistors. Many
benefits are realized as a direct result of using this mixed
technology. A simplified internal block diagram of the 33996 is
shown in Figure 1, page 2.
MCU INTERFACE DESCRIPTION
In operation the 33996 functions as a 16-output serial switch
serving as a microcontroller (MCU) bus expander and buffer
with fault management and fault reporting features. In doing so,
the device directly relieves the MCU of the fault management
functions.
The 33996 directly interfaces to an MCU and operates at
system clock serial frequencies up to 6.0 MHz using a Serial
Peripheral Interface (SPI) for control and diagnostic readout.
Figure 3 shows the basic SPI configuration between an MCU
and one 33996.
MC68HCXX
Microcontroller
33996
The 33996 may be controlled and provide diagnostics using
a daisy chain configuration or in parallel mode. Figure 4 shows
the daisy chain configuration using the 33996. Data from the
MCU is clocked daisy chain through each device while the Chip
Select bit (CS) is commanded low by the MCU. During each
clock cycle, output status from the daisy-chained 33996s is
being transferred back to the MCU via the Master In Slave Out
(MISO) line. On rising edge of CS, data stored in the input
register is transferred to the output driver. Daisy chain control of
the 33996 requires 24 bits per device.
Multiple 33996 devices can be controlled in a parallel input
fashion using the SPI. Figure 5, page 10, illustrates potentially
32 loads being controlled by two dedicated parallel MCU ports
used for chip select.
Shift Register
MOSI
MISO
SI
24-Bit Shift Register
SO
Receive
Buffer
Parallel
Ports
SCLK
RST
CS
PWM
To Logic
MC68HCXX
Microcontroller
Shift Register
MOSI
MISO
SCLK
Parallel
Ports
PWM1
PWM2
33996
SI
SO
SCLK
CS
PWM
RST
Figure 3. 33996 SPI Interface with Microcontroller
All inputs are compatible with 3.3 V/5.0 V CMOS logic levels
and incorporate positive logic. An input that is programmed to a
logic low state (< 0.8 V) will have the corresponding output
OFF. Conversely, an input programmed to a logic high state
(> 2.2 V) will have the output being controlled ON. Diagnostics
is treated in a similar manner—outputs with a fault will feedback
(via SO) to the MCU a logic [1], while normal operating outputs
will provide a logic [0].
33996
SI
SO
SCLK
CS
PWM
RST
Figure 4. 33996 SPI System Daisy Chain
MOTOROLA ANALOG INTEGRATED CIRFCoUrITMDoErVeICEInDfAoTrAmation On This Product,
Go to: www.freescale.com
33996
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