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SLLA252 – JULY 2006
The PCI7x20 PHY-layer requires only an external 24.576-MHz crystal as a reference for the cable ports. An
external clock may be provided instead of a crystal. An internal oscillator drives an internal phase-locked loop
(PLL), which generates the required 393.216-MHz reference signal. This reference signal is internally divided to
provide the clock signals that control transmission of the outbound encoded strobe and data information. A
49.152-MHz clock signal is supplied to the integrated LLC for synchronization and is used for resynchronization
of the received data. Data bits to be transmitted through the cable ports are received from the integrated LLC
and are latched internally in synchronization with the 49.152-MHz system clock. These bits are combined
serially, encoded, and transmitted at 98.304M, 196.608M, or 393.216M bits/s (referred to as S100, S200, or
S400 speeds, respectively) as the outbound data-strobe information stream. During transmission, the encoded
data information is transmitted differentially on the twisted-pair B (TPB) cable pair(s), and the encoded strobe
information is transmitted differentially on the twisted-pair A (TPA) cable pair(s).
Function 3 of the PCI7620 and PCI7420 devices is a dedicated socket that supports SD, MMC, Memory Stick,
and Memory Stick-Pro cards. The Flash Media dedicated socket provides separate terminals for SD/MMC and
Memory Stick signals so that both an SD/MMC card and a Memory Stick/Memory Stick-Pro card can be used
concurrently.
Various implementation specific functions and general-purpose inputs and outputs are provided through eight
multifunction terminals. These terminals present a system with options in PCI LOCK, serial and parallel
interrupts, PC Card activity indicator LEDs, and other platform specific signals. PCI-compliant general-purpose
events may be programmed and controlled through the multifunction terminals, and an ACPI-compliant
programming interface is included for the general-purpose inputs and outputs.
The PCI7x20 device is compliant with the latest PCI Bus Power Management Specification, and provides
several low-power modes, which enable the host power system to further reduce power consumption.
The PCI7x20 device also has a three-pin serial interface compatible with both the Texas Instruments TPS2226
and TPS2228 power switches. The TPS2226 or TPS2228 power switch provides power to the two CardBus
sockets on the PCI7x20 device. The power to each dedicated socket is controlled through separate power
control terminals. Each of these power control pins can be connected to an external 3.3-V power switch.
NOTE:
This product is for high-volume PC applications only. For a complete datasheet or
more information contact support@ti.com.
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