Another interface circuit for the MAX1403 is shown. It can be seen from the figure that the interface circuit consumes less I/O ports and the circuit is more compact. All I/O pins of the microcontroller can be interfaced with the MAX1403. If a bidirectional open-drain I/O pin is active, DOUT can be tied to DIN to further reduce the number of interface pins. To use the MAX1403 three-wire interface, the CS pin in the figure must be grounded.
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