Texas Instruments PCI7411, PCI7611 Internal Ring Oscillator, 3. TPS2228 Control Logic-xVPP/VCORE

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