82374EB datasheet(85/208 Pages) INTEL

85 / 208 page

82374EB82374SB

Bit

Description

Rotate and EOI Codes (R SL EOI)

These three bits control the Rotate and End of Interrupt modes

and combinations of the two A chart of these combinations is listed above under the bit definition

Bits 75

Function

001

Non-specific EOI command

011

Specific EOI Command

101

Rotate on Non-Specific EOI Command

100

Rotate in Auto EOI Mode (Set)

000

Rotate in Auto EOI Mode (Clear)

111

Rotate on Specific EOI Command

110

Set Priority Command

010

No Operation

L0 - L2 Are Used

OCW2 Select

When selecting OCW2 bits 3 and 4 must both be 0 If bit 4 is a 1 the interrupt

controller interprets the write to this port as an ICW1 Therefore always ensure that these bits are both

0 when writing an OCW2

Interrupt Level Select (L2 L1 L0)

L2 L1 and L0 determine the interrupt level acted upon when the

SL bit is active A simple binary code outlined above selects the channel for the command to act

upon When the SL bit is inactive these bits do not have a defined function programming L2 L1 and

L0 to 0 is sufficient in this case

Bit 20

Interrupt Level

000

IRQ 0(8)

001

IRQ 1(9)

010

IRQ 2(10)

011

IRQ 3(11)

100

IRQ 4(12)

101

IRQ 5(13)

110

IRQ 6(14)

111

IRQ 7(15)

348 OCW3OPERATION CONTROL WORD 3

020hINT CNTRL-1

0A0hINT CNTRL-2

Default Value

x01xxx10b

Attribute

ReadWrite

Size

8 Bits

OCW3 serves three important functions Enable Special Mask Mode Poll Mode control and IRRISR register

read control

First OCW3 is used to set or reset the Special Mask Mode (SMM) The Special Mask Mode can be used by an

interrupt service routine to dynamically alter the system priority structure while the routine is executing through

selective enablingdisabling of the other channel’s mask bits

Second the Poll Mode is enabled when a write to OCW3 is issued with Bit 2 equal to 1 The next IO read to

the interrupt controller is treated like an interrupt acknowledge a binary code representing the highest priority

level interrupt request is released onto the bus

82374EB Folha de dados(PDF) 85 Page - Intel Corporation

82374EB Folha de dados(HTML) 85 Page - Intel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Folha de dados Download

Ligação URL