[微机实验/TD-PITE] 8259 中断优先级实验+选做实验

实验内容

程序开始时 LED 灯 D7-D0 全亮。
按下单脉冲开关 KK1，响应 IR6 中断请求，使绿灯（D3-D0）亮，红灯（D7-D4）灭。
按下单脉冲开关 KK2，响应 IR7 中断请求，使红灯（D7-D4）亮，绿灯（D3-D0）灭。

实验接线

LED 连接 8255 的 B 口，KK1+ 连接 MIR6，KK2+ 连接 MIR7。如下图所示：

代码

1
CODE SEGMENT
2
ASSUME CS:CODE
3

4
START:
5
  MOV AX, 0
6
  MOV DS, AX
7

8
  ;; INIT 8255
9
  MOV DX, 0646H
10
  MOV AL, 90H ;; 10010000B, INPUT FROM A & OUTPUT TO B
11
  OUT DX, AL
12

13
  ;; MIR6
14
  MOV AX, OFFSET MIR6 ;; PUT CS:IP TO INTERRUPT VECTOR ADDRESS
15
                      ;; 6: 38H - 3BH
16
                      ;; IP -> 38H
17
                      ;; CS -> 3AH
18
  MOV SI, 38H
19
  MOV [SI], AX
20
  MOV AX, CS
21
  MOV SI, 3AH
22
  MOV [SI], AX
23

24
  ;; MIR7
25
  MOV AX, OFFSET MIR7 ;; 7: 3CH - 3FH
26
                      ;; IP -> 3CH
27
                      ;; CS -> 3AH
28
  MOV SI, 3CH
29
  MOV [SI], AX
30
  MOV AX, CS
31
  MOV SI, 3EH
32
  MOV [SI], AX
33

34
  ;; --------------------------------------------------
35
  ;; INIT 8259
36
  CLI ;; DISABLE INTERRUPT
37
  MOV AL, 11H ;; ICW1 00010001B
38
              ;;      ----A-BC
39
              ;; A: 1=HIGH, 0=UPPER EDGE
40
              ;; B: 1=SINGLE, 0=MULTIPLE
41
              ;; C: NEED ICW4
42
  OUT 20H, AL
43
  MOV AL, 08H ;; ICW2 00001000B
44
              ;;
45
  OUT 21H, AL
46
  MOV AL, 04H ;; ICW3 00000100B
47
              ;;      -----AB-
48
              ;; A: 1 = INNER SUB 8259 CONNECTED TO IR2
49
              ;;    0 = NOT USED
50
              ;; B: ANY 8259 CONNECTED TO MAIN IR1
51
  OUT 21H, AL
52
  MOV AL, 07H ;; ICW4 00000111B
53
              ;;      ----ABC-
54
              ;; A: 1 = BUFFERED
55
              ;;    0 = NOT BUFFERED
56
              ;; B: 1 = MAIN
57
              ;;    0 = SUB
58
              ;; C: 1 = AUTO INTERRUPT STOP
59
              ;;    0 = NOT AUTO
60
  OUT 21H, AL
61
  MOV AL, 2FH ;; OCW1 00101111B
62
              ;;   M7 - M0
63
              ;;   0 = ALLOWED
64
              ;;   1 = DISABLED
65
              ;; IR4 IS USED TO COMMUNICATE WITH PC
66
  OUT 21H, AL
67
  STI ;; ALLOW INTERRUPT
68
  ;; --------------------------------------------------
69

70
AA1: ;; MAIN
71
  MOV DX, 0642H
72
  MOV AL, 0FFH
73
  OUT DX, AL
74
  JMP AA1
75

76
MIR6:
77
  MOV DX, 0642H
78
  MOV AL, 0FH ;; GREEN LIGHT
79
  OUT DX, AL
80
  CALL DELAY
81
  IRET
82

83
MIR7:
84
  MOV DX, 0642H
85
  MOV AL, 0F0H
86
  OUT DX, AL ;; RED LIGHT
87
  CALL DELAY
88
  IRET
89

90
DELAY PROC NEAR
91
  MOV CX, 0FFFFH
92
  LOOP $
93
  MOV CX, 0FFFFH
94
  LOOP $
95
  MOV CX, 0FFFFH
96
  LOOP $
97
  MOV CX, 0FFFFH
98
  LOOP $
99
  RET
100
DELAY ENDP
101

102
CODE ENDS
103
END START

选做实验 1

描述

使用单脉冲开关控制 LED 的移动方向，初始状态仅点亮 D7。

当 KK1 按下时，LED 灯向右移动；当 KK2 按下时，LED 灯向左移动；当 LED 灯移动到单侧边界时，停止移动。

分析

需要保存当前移动的状态，使得中断嵌套执行完后原中断不继续执行。

代码

1
CODE SEGMENT
2
ASSUME CS:CODE
3

4
START:
5
  ;; BH: MODIFIED
6
  ;; BL: STATUS
7
  MOV BX, 0080H
8

9
  ;; INIT 8255
10
  MOV DX, 0646H
11
  MOV AL, 90H ;; 10010000B, INPUT FROM A & OUTPUT TO B
12
  OUT DX, AL
13

14
  ;; MIR6
15
  MOV AX, OFFSET MIR6 ;; PUT CS:IP TO INTERRUPT VECTOR ADDRESS
16
                      ;; 6: 38H - 3BH
17
                      ;; IP -> 38H
18
                      ;; CS -> 3AH
19
  MOV SI, 38H
20
  MOV [SI], AX
21
  MOV AX, CS
22
  MOV SI, 3AH
23
  MOV [SI], AX
24

25
  ;; MIR7
26
  MOV AX, OFFSET MIR7 ;; 7: 3CH - 3FH
27
                      ;; IP -> 3CH
28
                      ;; CS -> 3AH
29
  MOV SI, 3CH
30
  MOV [SI], AX
31
  MOV AX, CS
32
  MOV SI, 3EH
33
  MOV [SI], AX
34

35
  ;; --------------------------------------------------
36
  ;; INIT 8259
37
  CLI ;; DISABLE INTERRUPT
38
  MOV AL, 11H ;; ICW1 00010001B
39
              ;;      ----A-BC
40
              ;; A: 1=HIGH, 0=UPPER EDGE
41
              ;; B: 1=SINGLE, 0=MULTIPLE
42
              ;; C: NEED ICW4
43
  OUT 20H, AL
44
  MOV AL, 08H ;; ICW2 00001000B
45
              ;;
46
  OUT 21H, AL
47
  MOV AL, 04H ;; ICW3 00000100B
48
              ;;      -----AB-
49
              ;; A: 1 = INNER SUB 8259 CONNECTED TO IR2
50
              ;;    0 = NOT USED
51
              ;; B: ANY 8259 CONNECTED TO MAIN IR1
52
  OUT 21H, AL
53
  MOV AL, 07H ;; ICW4 00000111B
54
              ;;      ----ABC-
55
              ;; A: 1 = BUFFERED
56
              ;;    0 = NOT BUFFERED
57
              ;; B: 1 = MAIN
58
              ;;    0 = SUB
59
              ;; C: 1 = AUTO INTERRUPT STOP
60
              ;;    0 = NOT AUTO
61
  OUT 21H, AL
62
  MOV AL, 2FH ;; OCW1 00101111B
63
              ;;   M7 - M0
64
              ;;   0 = ALLOWED
65
              ;;   1 = DISABLED
66
              ;; IR4 IS USED TO COMMUNICATE WITH PC
67
  OUT 21H, AL
68
  STI ;; ALLOW INTERRUPT
69
  ;; --------------------------------------------------
70

71
AA1: ;; MAIN
72
  MOV DX, 0642H
73
  MOV AL, BL
74
  OUT DX, AL
75
  JMP AA1
76

77
MIR6:
78
  STI
79
  MOV BH, 1
80
  MOV DX, 0642H
81

82
IR6_RIGHT:
83
  CMP BL, 1 ;; MOST RIGHT
84
  JE IR6_STOP
85
  SHR BL, 1
86
  MOV AL, BL
87
  OUT DX, AL
88
  CALL DELAY
89
  CMP BH, 1 ;; CHECK WHETHER NESTED INTERRUPT HAPPENED
90
  JNE IR6_STOP
91
  JMP IR6_RIGHT
92

93
IR6_STOP:
94
  MOV BH, 0
95
  IRET
96

97
MIR7:
98
  STI
99
  MOV BH, 1
100
  MOV DX, 0642H
101

102
IR7_LEFT:
103
  CMP BL, 80H ;; MOST LEFT
104
  JE IR7_STOP
105
  SHL BL, 1
106
  MOV AL, BL
107
  OUT DX, AL
108
  CALL DELAY
109
  CMP BH, 1 ;; CHECK WHETHER NESTED INTERRUPT HAPPENED
110
  JNE IR7_STOP
111
  JMP IR7_LEFT
112

113
IR7_STOP:
114
  MOV BH, 0
115
  IRET
116

117
DELAY PROC NEAR
118
  MOV CX, 0FFFFH
119
  LOOP $
120
  MOV CX, 0FFFFH
121
  LOOP $
122
  MOV CX, 0FFFFH
123
  LOOP $
124
  MOV CX, 0FFFFH
125
  LOOP $
126
  RET
127
DELAY ENDP
128

129
CODE ENDS
130
END START

选做实验 2

描述

在选做实验 1 的基础上，增加：

在向左移动过程中，如果要求其向右移动，则立即改变方向，向右移动。到最右侧后，向左移动到最左侧。
在向右移动中，如果要求其向左移动，不立即改变方向，等到移动到最右侧后再开始向左移动。

分析

在当前移动状态的基础上，增加是否需要向左移动的标志。在向右移动中断处理程序（MIR6）的最后，当需要向左移动时，则调用向左移动中断处理程序（MIR7）。

代码

1
CODE SEGMENT
2
ASSUME CS:CODE
3

4
START:
5
  ;; BH: MODIFIED
6
  ;;   00 = IDLE
7
  ;;   01 = GOING_LEFT
8
  ;;   10 = GOING_RIGHT
9
  ;;   11 = GOING_RIGHT(DEFER GO RIGHT)
10
  ;; BL: STATUS
11
  MOV BX, 0080H
12

13
  ;; INIT 8255
14
  MOV DX, 0646H
15
  MOV AL, 90H ;; 10010000B, INPUT FROM A & OUTPUT TO B
16
  OUT DX, AL
17

18
  ;; MIR6
19
  MOV AX, OFFSET MIR6 ;; PUT CS:IP TO INTERRUPT VECTOR ADDRESS
20
                      ;; 6: 38H - 3BH
21
                      ;; IP -> 38H
22
                      ;; CS -> 3AH
23
  MOV SI, 38H
24
  MOV [SI], AX
25
  MOV AX, CS
26
  MOV SI, 3AH
27
  MOV [SI], AX
28

29
  ;; MIR7
30
  MOV AX, OFFSET MIR7 ;; 7: 3CH - 3FH
31
                      ;; IP -> 3CH
32
                      ;; CS -> 3AH
33
  MOV SI, 3CH
34
  MOV [SI], AX
35
  MOV AX, CS
36
  MOV SI, 3EH
37
  MOV [SI], AX
38

39
  ;; --------------------------------------------------
40
  ;; INIT 8259
41
  CLI ;; DISABLE INTERRUPT
42
  MOV AL, 11H ;; ICW1 00010001B
43
              ;;      ----A-BC
44
              ;; A: 1=HIGH, 0=UPPER EDGE
45
              ;; B: 1=SINGLE, 0=MULTIPLE
46
              ;; C: NEED ICW4
47
  OUT 20H, AL
48
  MOV AL, 08H ;; ICW2 00001000B
49
              ;;
50
  OUT 21H, AL
51
  MOV AL, 04H ;; ICW3 00000100B
52
              ;;      -----AB-
53
              ;; A: 1 = INNER SUB 8259 CONNECTED TO IR2
54
              ;;    0 = NOT USED
55
              ;; B: ANY 8259 CONNECTED TO MAIN IR1
56
  OUT 21H, AL
57
  MOV AL, 07H ;; ICW4 00000111B
58
              ;;      ----ABC-
59
              ;; A: 1 = BUFFERED
60
              ;;    0 = NOT BUFFERED
61
              ;; B: 1 = MAIN
62
              ;;    0 = SUB
63
              ;; C: 1 = AUTO INTERRUPT STOP
64
              ;;    0 = NOT AUTO
65
  OUT 21H, AL
66
  MOV AL, 2FH ;; OCW1 00101111B
67
              ;;   M7 - M0
68
              ;;   0 = ALLOWED
69
              ;;   1 = DISABLED
70
              ;; IR4 IS USED TO COMMUNICATE WITH PC
71
  OUT 21H, AL
72
  STI ;; ALLOW INTERRUPT
73
  ;; --------------------------------------------------
74

75
AA1: ;; MAIN
76
  MOV DX, 0642H
77
  MOV AL, BL
78
  OUT DX, AL
79
  JMP AA1
80

81
;; --------------------------------------------------
82
MIR6: ;; INTEND TO GO RIGHT
83
  STI
84
  MOV DX, 0642H
85

86
  ;; PRESS KK1 WHEN GOING RIGHT
87
  TEST BH, 10B
88
  JNZ IR6_EXIT_IRET
89

90
  ;; BH MUST BE 0 OR 1
91
  ;; BH = 0 ==> MOV BH, 10B
92
  ;; BH = 1 ==> MOV BH, 11B
93
  OR BH, 10B
94

95
IR6_RIGHT:
96
  CMP BL, 1 ;; MOST RIGHT
97
  JE IR6_LEFT
98
  SHR BL, 1
99
  MOV AL, BL
100
  OUT DX, AL
101
  CALL DELAY
102
  JMP IR6_RIGHT
103

104
IR6_LEFT:
105
  TEST BH, 1 ;; NEED TO GO LEFT
106
  JZ IR6_EXIT
107
  MOV BH, 1 ;; SET MODE TO GOING_LEFT
108
  JMP MIR7
109
IR6_EXIT: ;; NORMAL EXIT
110
  MOV BH, 0
111
IR6_EXIT_IRET:
112
  IRET
113

114
;; --------------------------------------------------
115
MIR7: ;; INTEND TO GO LEFT
116
  STI
117
  TEST BH, 10B ;; GOING TO RIGHT NOW
118
  JNZ IR7_IRET ;; EXIT
119
  MOV BH, 1
120
  MOV DX, 0642H
121

122
IR7_LEFT:
123
  CMP BL, 80H ;; MOST LEFT
124
  JE IR7_STOP
125
  SHL BL, 1
126
  MOV AL, BL
127
  OUT DX, AL
128
  CALL DELAY
129
  CMP BH, 1 ;; WHETHER TO CONTINUE GOING LEFT
130
  JNE IR7_STOP
131
  JMP IR7_LEFT
132

133
IR7_STOP:
134
  MOV BH, 0 ;; BACK TO IDLE
135
  IRET
136
IR7_IRET:
137
  OR BH, 01B ;; GO TO LEFT AFTER RIGHT FINISHED
138
  IRET
139

140
DELAY PROC NEAR
141
  MOV CX, 0FFFFH
142
  LOOP $
143
  MOV CX, 0FFFFH
144
  LOOP $
145
  MOV CX, 0FFFFH
146
  LOOP $
147
  MOV CX, 0FFFFH
148
  LOOP $
149
  RET
150
DELAY ENDP
151

152
CODE ENDS
153
END START

[微机实验/TD-PITE] 8259 中断优先级实验+选做实验

ToC

实验内容

实验接线

代码

选做实验 1

描述

分析

代码

选做实验 2

描述

分析

代码