CS4205 Datasheet, PDF (73/80 Pages) Cirrus Logic – CrystalClear Audio Codec 97 with Portable Computing

CS4205
Misc. Digital Interface Pins
SPDO/SDO2 - Sony/Philips Digital Interface / Serial Data Output 2,Output, Pin 48
This pin generates the S/PDIF digital output from the CS4205 when the SPEN bit in the S/PDIF Control
Register (Index 68h) is ‘set’. This output may be used to directly drive a resistive divider and coupling
transformer to an RCA-type connector for use with consumer audio equipment. This pin also provides
the serial data for the second serial data port when the SDO2 bit in the Serial Port Control Register
(Index 6Ah) is ‘set’. These two functions are mutually exclusive. When neither function is being used
this output is driven to a logic ‘0’.
EAPD/SCLK - External Amplifier Powerdown / Serial Clock, Output, Pin 47
This pin is used to control the powerdown state of an audio amplifier external to the CS4205. The
output is controlled by the EAPD bit in the Powerdown Ctrl/Stat Register (Index 26h). It is driven as a
normal CMOS output and defaults low (‘0’) upon power-up. This pin also provides the serial clock for all
serial data ports when the SDSC bit in the Serial Port Control Register (Index 6Ah) is ‘set’.
GPIO0/LRCLK - General Purpose I/O / Left-Right Clock, Input/Output, Pin 43
This pin is a general purpose I/O pin that can be used to interface with various external circuitry. When
configured as an input, it functions as a Schmitt triggered input with 350 mV hysteresis at 5 V and 220
mV hysteresis at 3.3 V. When configured as an output, it can function as a normal CMOS output (4 mA
drive) or as an open drain output. This pin also provides the L/R clock for all serial data ports when the
SDEN bit in the Serial Port Control Register (Index 6Ah) is ‘set’. This bit powers up in the high
impedance state for backward compatibility.
GPIO1/SDOUT - General Purpose I/O / Serial Data Ouput, Input/Output, Pin 44
This pin is a general purpose I/O pin that can be used to interface with various external circuitry. When
configured as an input, it functions as a Schmitt triggered input with 350 mV hysteresis at 5 V and 220
mV hysteresis at 3.3 V. When configured as an output, it can function as a normal CMOS output (4 mA
drive) or as an open drain output. This pin also provides the serial data for the first serial data port when
the SDEN bit in the Serial Port Control Register (Index 6Ah) is ‘set’. This bit powers up in the high
impedance state for backward compatibility.
GPIO2/SDI1 - General Purpose I/O / Serial Data Input 1, Input/Output, Pin 39
This pin is a general purpose I/O pin that can be used to interface with various external circuitry. When
configured as an input, it functions as a Schmitt triggered input with 350 mV hysteresis at 5 V and 220
mV hysteresis at 3.3 V. When configured as an output, it can function as a normal CMOS output (4 mA
drive) or as an open drain output. This pin also receives the serial data for the first serial input port
when the SDI1 bit in the Serial Port Control Register (Index 6Ah) is ‘set’. This bit powers up in the high
impedance state for backward compatibility.
GPIO3/SDI2 - General Purpose I/O / Serial Data Input 2, Input/Output, Pin 40
This pin is a general purpose I/O pin that can be used to interface with various external circuitry. When
configured as an input, it functions as a Schmitt triggered input with 350 mV hysteresis at 5 V and 220
mV hysteresis at 3.3 V. When configured as an output, it can function as a normal CMOS output (4 mA
drive) or as an open drain output. This pin also receives the serial data for the second serial input port
when the SDI2 bit in the Serial Port Control Register (Index 6Ah) is ‘set’. This bit powers up in the high
impedance state for backward compatibility.
DS489PP2
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