STPCI2 STMicroelectronics, STPCI2 Datasheet - Page 84

• Manufacturer Part Number: STPCI2
• Description: STPC ATLAS DATASHEET - X86 CORE PC COMPATIBLE SYS
• Manufacturer: STMicroelectronics

DESIGN GUIDELINES
6.3.6. IPC
Most of the IPC signals are multiplexed: Interrupt
inputs, DMA Request inputs, DMA Acknowledge
outputs. The figure below describes a complete
implementation of the IRQ[15:0] time-multiplexing.
When the interface is integrated into the STPC,
the corresponding interrupt line can be grounded
as it is connected internally.
For example, if the integrated IDE controller is
activated, the IRQ[14] and IRQ[15] inputs can be
grounded.
84/111
Timer 0
Keyboard
Slave PIC
COM2/COM4
COM1/COM3
LPT2
Floppy
LPT1
RTC
Mouse
FPU
PCI / IDE
PCI / IDE
Figure 6-11. Typical IRQ multiplexing
ISA_CLK2X
ISA_CLK
Issue 1.0 - July 24, 2002
IRQ[0]
IRQ[1]
IRQ[2]
IRQ[3]
IRQ[4]
IRQ[5]
IRQ[6]
IRQ[7]
IRQ[8]
IRQ[9]
IRQ[10]
IRQ[11]
IRQ[12]
IRQ[13]
IRQ[14]
IRQ[15]
Floppy
When an interrupt line is used internally, the
corresponding input can be grounded. In most of
the embedded designs, only few interrupts lines
are necessary and the glue logic can be simplified.
1C0
1C1
1C2
1C3
2C0
2C1
2C2
2C3
A
B
1C0
1C1
1C2
1C3
2C0
2C1
2C2
2C3
A
B
74x153
74x153
1G
1G
2G
2G
1Y
2Y
1Y
2Y
IRQ_MUX[0]
IRQ_MUX[1]
IRQ_MUX[2]
IRQ_MUX[3]