Filter
Top Products
System Features Selection
1-4
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.
1.1.6 PCI 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.
1.1.7 Socket 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 P
2
CCLK bit (system control register, PCI offset 80h, bit 27).
1.1.8 Distributed 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.)
1.1.9 Optional PCI Signals
1.1.9.1 CLKRUN
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.
1.1.9.2 LOCK
This signal can be assigned on the MFUNC1, MFUNC3 or MFUNC7 terminal.