RB5C396 Ricoh Corporation, RB5C396 Datasheet - Page 57

• Manufacturer Part Number: RB5C396
• Description: PC Card Controller Compliant With Pcmcia 2.1/jeida 4.2
• Manufacturer: Ricoh Corporation

5. Connecting Multiple Units of RF5C296 or RF5C396
must be provided with independent indexes by connecting a pull-up or pull-down resistor to the SPKROUT# and
RI_OUT# pins. (For details, see “7. Plural Slot System” in “FUNCTIONAL DESCRIPTION” and “1. Initial Value
Setting Pins” in “HARDWARE DESIGN CONSIDERATIONS”)
consideration of a conflict between interrupt request signals. Driving software for ordinary PC card controllers
assigns the same IRQ number to different interrupt signals derived from the PC card status change. Such assign-
ment causes a conflict between interrupt request signals. This problem can be solved by the following three mea-
sures :
(1) Confining IRQn interrupt request signals derived from the PC card status change to any one unit of the
RF5C296 or the RF5C396 and applying polling to the other units at the sacrifice of increased overall current con-
sumption resulting from constant system operation.
(2) Re-designing driver software to assign different IRQn pins to interrupt request signals derived from the PC card
status change for each IC core at the sacrifice of additional recourse to the IRQn pins which are originally deficient
as resources.
(3) Connecting the IRQn pins as shown in the diagram below at the sacrifice of additional hardware installation.
Basically, the IRQn pins for assigning the same IRQ number to interrupt request signals derived from the PC card
status change would be sufficient to implement the hardware configuration shown in the diagram below. In any
ordinary system, however, the same IRQ number cannot always be assigned to interrupt request signals derived
from the PC card status change, resulting in many cases where circuit change cannot be confined to the single IRQn
pin.
Under the supply voltage of 3.3V, diode selection requires sufficient care to regulate a voltage drop to a small value.
To connect multiple units of the RF5C296 or the RF5C396 to the same system bus, their respective PC card slots
Multiple connections to the system bus are wired OR using the IRQn pins. The IRQn pins should be used in
IRQn1
IRQn2
Notice
Pull-down resistor on system side
RF5C296/RF5C396L/RB5C396/RF5C396
IRQn
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