X hits on this document

38 views

0 shares

0 downloads

0 comments

3 / 15

128 PC Interfacing, Communications and Windows Programming

It can be seen that the interface between the processor and the TXC device has an ad- dress bus from A3 to A31. These provide access to addresses in banks of 8 bytes. The byte enable lines ( HBE0 HBE7 ) provide the lower address lines. Thus, 8 bits, 16 bits, 32 bits or 64 bits can be accessed at a time. For example, to address the 8 bytes from the following binary address:

0110 1110 0000 0110 0110 0110 0110 XXXXb

then the address:

6E00666xh

would be put on the address bus. Then to access the 16 bits from 6E06661h to 6E06662h then the HBE1 and HBE2 lines would be made active, all the other byte lines will be inac- tive.

It can be seen that the TXC device handles most of the processor signals. The PIIX3 device handles all the interrupts within the computer (IRQ0IRQ15 and PCIRQAPCIRQD) and connects directly to the interrupt line of the processor. This device also allows inter- rupts to be steered to unassigned interrupt and allow supports plug-and-play. The other direct connection from the processor to the PIIX3 device is for the math co-processor error interrupt.

11.3 82371SB PCI ISA Xcelerator (PIIX3)

The PIIX3 is a 208-pin QFP (Quad flat pack) IC which integrates much of the function- ality of the ISA bus interface onto a single device. Table 11.1 outlines the main connec- tions to the PIIX3 IC. The PIIX4 is a 324-pin device.

Signal

Pin

Signal

Pin

Signal

Pin

Signal

Pin

AD0

206

IRQ1

4

BALE

64

SA8/DD0

55

AD1

205

IRQ3

58

AEN

20

SA9/DD1

50

AD2

204

IRQ4

56

LA17

86

SA10/DD2

49

AD3

203

IRQ5

34

LA18

84

SA11/DD3

48

AD4

202

IRQ6

33

LA19

82

SA12/DD4

47

AD5

201

IRQ7

32

LA20

80

SA13/DD5

46

AD6

200

-IRQ8

5

LA21

76

SA14/DD6

45

AD7

199

IRQ9

10

LA22

74

SA15/DD7

44

AD8

197

IRQ10

73

LA23

72

SA16/DD8

43

AD9

194

IRQ11

75

SA0

69

SA17/DD9

41

AD10

193

IRQ12/M

77

SA1

68

SA18/DD10

40

AD11

192

IRQ14

83

SA2

67

SA19/DD11

39

AD12

191

IRQ15

81

SA3

66

SA20/DD12

38

SA4

63

SA21/DD13

37

SA5

61

SA22/DD14

36

SA6

59

SA23/DD15

35

SA7

57

-OWS

15

DRQ0

87

-SMEMW

22

DRQ1

30

-SMEMR

19

DRQ2

12

-IOW

24

DRQ3

25

-IOR

23

AD13

190

AD14

189

AD15

188

AD16

177

AD17

176

AD18

175

AD19

174

AD20

173

PCI Address/ Data lines

IRQ lines

Table 11.1

PIIX3 connections.

ISA lines

ISA lines

Document info
Document views38
Page views38
Page last viewedWed Dec 07 17:14:05 UTC 2016
Pages15
Paragraphs1354
Words5176

Comments