MC33298P Freescale Semiconductor, MC33298P Datasheet - Page 14

• Manufacturer Part Number: MC33298P
• Description: IC SWITCH SERIAL OCTAL 20-DIP
• Manufacturer: Freescale Semiconductor
• Type: Low Sider

Specifications of MC33298P

• Input Type: SPI
• Number Of Outputs: 8
• On-state Resistance: 350 mOhm
• Current - Output / Channel: 1A
• Current - Peak Output: 6A
• Voltage - Supply: 9 V ~ 26.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

coupled to an MCU, it receives ON/OFF commands from the
MCU and in return transmits the drain status of the device’s
output switches. Many devices can be daisy-chained
together, forming a larger system, illustrated in
port (aside from the required SPI) is required for chip select
to control 32 possible loads.
input fashion using the SPI, illustrated in
figure shows a possible 24 loads being controlled by only
three dedicated parallel MCU ports used for chip select.
33298 devices using two MCUs. A system can have only one
master MCU at any given instant of time and one or more
slave MCUs. Master control of the system must pass from
one MCU to the other in an orderly manner. The master MCU
14
33298
FUNCTIONAL DESCRIPTION
INTRODUCTION
Microcontroller
One main advantage of the 33298 is the serial port. When
Note In this example, only one dedicated MCU parallel
Multiple 33298 devices can also be controlled in a parallel
Figure 16
Parallel
Ports
MC68XX
SPI
Microcontroller
Figure 15. Parallel Input SPI Control
A
B
C
illustrates a basic method of controlling multiple
MC68XX
SPI
MOSI
SCLK
SCLK
Parallel Port
MISO
IRQ
MOSI
CS
SO
8 Outputs
SI
SCLK
CS
SI
SCLK
CS
SI
SCLK
CS
33298
Figure
Figure 14. 33298 SPI System Daisy Chain
33298
33298
33298
SCLK
Figure
15. This
SI
8 Outputs
8 Outputs
8 Outputs
14.
CS
SO
8 Outputs
33298
supplies the system clock signal (top MCU designated the
master); the lower MCU being the slave. It is possible to have
a system with more than one master; however, not at the
same time. Only when the master is not communicating can
a slave assume the mastership and communicate. MCU
master control is switched through the use of the slave select
(SS) pin of the MCUs. A master will become a slave when it
detects a logic low state on its SS pin.
applications where a large number of loads require efficient
control. To this end, the popular Synchronous Serial
Peripheral Interface (SPI) protocol is incorporated to
communicate efficiently with the MCU.
SPI SYSTEM ATTRIBUTES
with numerous standard peripherals and MCUs available
from Freescale Semiconductor and other semiconductor
manufacturers. SPI reduces the number of pins necessary
for input/output (I/O) on the 33298. It also offers an easy
means of expanding the I/O function using few MCU pins.
The SPI system of communication consists of the MCU
transmitting, in return it receives one data-bit of information
per system clock cycle.
one pin, Microcontroller Out Serial In (MOSI), and received
by another pin, Microcontroller In Serial Out (MISO), of
the MCU.
• Full duplex, three-wire synchronous data transfer
• Each microcontroller can be a master or a slave
• Provides write collision flag protection
• Provides end of message interrupt flag
• Four I/Os associated with SPI (MOSI, MISO, SCLK, SS)
• An MCU is required for efficient operational control
• In contrast to parallel input control it Is slower at
SCLK
These basic examples make the 33298 very attractive for
The SPI system is flexible enough to communicate directly
Data-bits of information are simultaneously transmitted by
Some features of the SPI are:
Drawbacks to SPI are:
performing pulse width modulating (PWM) functions.
SI
CS
SO
8 Outputs
33298
SCLK
Analog Integrated Circuit Device Data
SI
Freescale Semiconductor
CS
SO
8 Outputs
33298
SCLK
SI