33972 Просмотр технического описания (PDF) - Motorola => Freescale
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33972 Datasheet PDF : 28 Pages
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Freescale Semiconductor, Inc.
MCU INTERFACE DESCRIPTION
The 33972 device directly interfaces to a 3.3 V or 5.0 V
microcontroller unit (MCU). SPI serial clock frequencies up to
6.0 MHz may be used for programming and reading switch
input status (production tested at 4.16 MHz). Figure 5 illustrates
the configuration between an MCU and one 33972.
Serial peripheral interface (SPI) data is sent to the 33972
device through the SI input terminal. As data is being clocked
into the SI terminal, status information is being clocked out of
the device by the SO output terminal. The response to a SPI
command will always return the switch status, interrupt flag, and
thermal flag. Input switch states are latched into the SO register
on the falling edge of the chip select (CS) terminal. Twenty-four
bits are required to complete a transfer of information between
the 33972 and the MCU.
MC68HCXX
Microcontroller
Shift Register
MOSI
MISO
33972
SI
24-Bit Shift Register
SO
MC68HCXX
Microcontroller
Shift Register
MOSI
MISO
SCLK
Parallel
Ports
INT
33972
SI
SO
SCLK
CS
INT
33972
SI
SO
SCLK
CS
INT
SCLK
Figure 6. SPI Parallel Interface with Microprocessor
Receive
Buffer
Parallel
Ports
INT
To Logic
CS
INT
Figure 5. SPI Interface with Microprocessor
Two or more 33972 devices may be used in a module
system. Multiple ICs may be SPI-configured in parallel or serial.
Figures 6 and 7 show the configurations. When using the serial
configuration, 48-clock cycles are required to transfer data in/
out of the ICs.
MC68HCXX
Microcontroller
Shift Register
MOSI
MISO
SCLK
Parallel
Ports
INT
33972
SI
SO
SCLK
CS
INT
33972
SI
SO
SCLK
CS
INT
Figure 7. SPI Serial Interface with Microprocessor
MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA
For More Information On This Product,
Go to: www.freescale.com
33972
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