System Features Selection
automatically assigned on the dedicated SDA and SCL terminals. A pullup resistor (typically 10 kΩ) must be added on SDA and SCL when using an EEPROM. The value of the pullup resistor can vary for different EEPROMs. Refer to the EEPROM data sheet or contact the manufacturer for the recommended pullup resistor value.
1.1.6PCI and ISA Style Interrupt
The PCI445X device provides three modes of interrupt signaling:
Parallel PCI interrupts only
Parallel PCI interrupts and serialized ISA interrupts
Serialized PCI interrupts and serialized ISA interrupts
Three PCI interrupts (INTA, INTB, and INTC) may be used and signaled in either the parallel mode using the MFUNC terminals or in the serial mode. The number of PCI interrupts may be reduced by setting the INTRTIE bit (system control register, PCI offset 80h, bit 29), which allows both the CardBus functions (function 0 and function 1) to report and use INTA or by setting the TIEALL bit (system control register, PCI offset 80h, bit 28) which allows all 3 functions (both CardBus + OHCI) to report and use INTA.
1.1.7Socket Power Switches
The PCI445X device supports TPS2206 and TPS2216 power switches. Refer to the detailed explanation on each data sheet. The interface between the power switch and the PCI445X device is serialized, so an external or internal clock source is required. By default an external power switch clock is assumed but this can be changed to use the oscillator internal to the PCI445X device by setting P2CCLK bit (system control register, PCI offset 80h, bit 27).
1.1.8Distributed DMA (DDMA)
Most of the systems do not use this function. This function needs PCGNT and PCREQ signals. PCGNT can be assigned to the MFUNC2 or MFUNC3 terminal. PCREQ can be assigned to the MFUNC0, MFUNC4, or MFUNC7 terminal. (See Section 1.3.4.5, Distributed DMA.)
1.1.9Optional PCI Signals
1.1.9.1CLKRUN
CLKRUN is the primary method for power reduction on the PCI bus. Most of the notebook PCs implement CLKRUN. The PCI445X device has a dedicated CLKRUN terminal. If it is not used, then a pulldown resistor is required to prevent oscillations on this input.
1.1.9.2LOCK
This signal can be assigned on the MFUNC1, MFUNC3 or MFUNC7 terminal.
