Texas Instruments PCI445X manual Important Information

Important Information

1.5 Important Information

This section clarifies important system implementation.

1.5.1G_RST Clamping Rail

G_RST is clamped to VCCP, so removing VCCP causes assertion of G_RST.

Figure 1±7. G_RST and VCCP Relationship

VCCP	VCCP = 0
	VCCP
	removed
G_RST	G_RST

All other signals with clamping rails behave the same way.

1.5.2PME/RI_OUT Bit Definition

If PME is selected, only PME is signaled on the PME/RI_OUT terminal. If RI_OUT is selected, only RI_OUT is signaled. The PCI445X device can signal PME and RI_OUT as completely separated signals. In this case RI_OUT should be assigned on the MFUNC terminal.

1.5.3Serialized IRQ Data Stream

PCI clock is needed for operation of the PCI445X serialized IRQ state-machine. During SUSPEND assertion, the PCI445X device stops the IRQSER stream. Before asserting SUSPEND, IRQSER must be stopped.

1.5.4Socket Power Control

An internal or external CLOCK source is needed for the socket power control through the P2C interface. The internal ring oscillator is on while the core VCC is applied to the PCI445X device. External CLOCK source is dependent on the system.

1.5.5External CLOCK Frequency for P2C Interface

If an external P2C CLOCK is used, then it will affect:

￿Advanced CD line noise filtering

￿VS test speed

￿TPS22X6 power control interface speed

Use of the internal ring oscillator is recommended. Recommended external CLOCK source is the 32.768-kHz real-time clock (RTC).

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