3.5.5Power Switch Interface

The power switch interface of the PCI7x21/PCI7x11 controller is a 3-pin serial interface. This 3-pin interface is implemented such that the PCI7x21/PCI7x11 controller can connect to both the TPS2226 and TPS2228 power switches. Bit 10 (12V_SW_SEL) in the general control register (PCI offset 86h, see Section 4.31) selects the power switch that is implemented. The PCI7x21/PCI7x11 controller defaults to use the control logic for the TPS2228 power switch. See Table 3−3 and Table 3−6 below for the power switch control logic.

Table 3−3. TPS2228 Control Logic—xVPP/VCORE

AVPP/VCORE CONTROL SIGNALS

OUTPUT

BVPP/VCORE CONTROL SIGNALS

OUTPUT

 

 

 

 

V_AVPP/VCORE

 

 

 

 

V_BVPP/VCORE

D8(SHDN)

D0

D1

D9

D8(SHDN)

D4

D5

D10

 

 

 

 

 

 

 

 

 

 

 

 

1

0

0

X

0 V

1

0

0

X

0 V

 

 

 

 

 

 

 

 

 

 

1

0

1

0

3.3 V

1

0

1

0

3.3 V

 

 

 

 

 

 

 

 

 

 

1

0

1

1

5 V

1

0

1

1

5 V

 

 

 

 

 

 

 

 

 

 

1

1

0

X

Hi-Z

1

1

0

X

Hi-Z

 

 

 

 

 

 

 

 

 

 

1

1

1

0

Hi-Z

1

1

1

0

Hi-Z

 

 

 

 

 

 

 

 

 

 

1

1

1

1

1.8 V

1

1

1

1

1.8 V

 

 

 

 

 

 

 

 

 

 

0

X

X

X

Hi-Z

0

X

X

X

Hi-Z

Table 3−4. TPS2228 Control Logic—xVCC

AVCC CONTROL SIGNALS

 

OUTPUT

BVCC CONTROL SIGNALS

 

OUTPUT

 

 

 

V_AVCC

 

 

 

V_BVCC

D8(SHDN)

D3

D2

D8(SHDN)

D6

D7

 

 

 

 

 

 

 

 

 

 

1

0

0

0 V

1

0

0

0 V

 

 

 

 

 

 

 

 

1

0

1

3.3 V

1

0

1

3.3 V

 

 

 

 

 

 

 

 

1

1

0

5 V

1

1

0

5 V

 

 

 

 

 

 

 

 

1

1

1

0 V

1

1

1

0 V

 

 

 

 

 

 

 

 

0

X

X

Hi-Z

0

X

X

Hi-Z

Table 3−5. TPS2226 Control Logic—xVPP

AVPP CONTROL SIGNALS

 

OUTPUT

BVPP CONTROL SIGNALS

 

OUTPUT

 

 

 

 

V_AVPP

 

 

 

 

 

V_BVPP

D8(SHDN)

D0

D1

D9

D8(SHDN)

D4

D5

 

D10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

0

X

0 V

1

0

0

 

X

0 V

 

 

 

 

 

 

 

 

 

 

 

1

0

1

0

3.3 V

1

0

1

 

0

3.3 V

 

 

 

 

 

 

 

 

 

 

 

1

0

1

1

5 V

1

0

1

 

1

5 V

 

 

 

 

 

 

 

 

 

 

 

1

1

0

X

12 V

1

1

0

 

X

12 V

 

 

 

 

 

 

 

 

 

 

 

1

1

1

X

Hi-Z

1

1

1

 

X

Hi-Z

 

 

 

 

 

 

 

 

 

 

 

0

X

X

X

Hi-Z

0

X

X

 

X

Hi-Z

Table 3−6. TPS2226 Control Logic—xVCC

AVCC CONTROL SIGNALS

 

OUTPUT

BVCC CONTROL SIGNALS

 

OUTPUT

 

 

 

V_AVCC

 

 

 

V_BVCC

D8(SHDN)

D3

D2

D8(SHDN)

D6

D7

 

 

 

 

 

 

 

 

 

 

1

0

0

0 V

1

0

0

0 V

 

 

 

 

 

 

 

 

1

0

1

3.3 V

1

0

1

3.3 V

 

 

 

 

 

 

 

 

1

1

0

5 V

1

1

0

5 V

 

 

 

 

 

 

 

 

1

1

1

0 V

1

1

1

0 V

 

 

 

 

 

 

 

 

0

X

X

Hi-Z

0

X

X

Hi-Z

3.5.6Internal Ring Oscillator

The internal ring oscillator provides an internal clock source for the PCI7x21/PCI7x11 controller so that neither the PCI clock nor an external clock is required in order for the PCI7x21/PCI7x11 controller to power down a socket or interrogate a PC Card. This internal oscillator, operating nominally at 16 kHz, is always enabled.

3−8

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Texas Instruments PCI7411 Internal Ring Oscillator, 3. TPS2228 Control Logic-xVPP/VCORE, 4. TPS2228 Control Logic-xVCC