MC33993 View Datasheet(PDF) - Motorola => Freescale
Part Name
Description
Manufacturer
MC33993 Datasheet PDF : 28 Pages
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MCU INTERFACE DESCRIPTION
The 33993 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 33993.
Serial peripheral interface (SPI) data is sent to the 33993
device through the SI input pin. As data is being clocked into the
SI pin, status information is being clocked out of the device by
the SO output pin. 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) pin. Twenty-four bits are required to
complete a transfer of information between the 33993 and the
MCU.
MC68HCXX
Microcontroller
Shift Register
MOSI
MISO
33993
SI
24-Bit Shift Register
SO
MC68HCXX
Microcontroller
Shift Register
MOSI
MISO
SCLK
Parallel
Ports
INT
33993
SI
SO
SCLK
CS
INT
33993
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 33993 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
33993
SI
SO
SCLK
CS
INT
33993
SI
SO
SCLK
CS
INT
Figure 7. SPI Serial Interface with Microprocessor
MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA
33993/D
11
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