Measurement Computing CIO-DAS160x/1x User Manual
Page 33
M1 = 0 is mode 0 for group B. Input / Output
M1 = 1 is mode 1 for group B. Strobed Input / Output
The Ports A, B, C High and C Low can be independently programmed for input or output.
The two groups of ports, group A and group B, can be independently programmed in one of several
modes. The most commonly used mode is mode 0, input / output mode. The codes for programming the
8255 in this mode are shown in Table 6-5 below.
Table 6-5. Programming Codes for the 82C55 Chip
IN
IN
IN
IN
155
9B
1
1
1
1
OUT
IN
IN
IN
154
9A
0
1
1
1
IN
OUT
IN
IN
153
99
1
0
1
1
OUT
OUT
IN
IN
152
98
0
0
1
1
IN
IN
OUT
IN
147
93
1
1
0
1
OUT
IN
OUT
IN
146
92
0
1
0
1
IN
OUT
OUT
IN
145
91
1
0
0
1
OUT
OUT
OUT
IN
144
90
0
0
0
1
IN
IN
IN
OUT
139
8B
1
1
1
0
OUT
IN
IN
OUT
138
8A
0
1
1
0
IN
OUT
IN
OUT
137
89
1
0
1
0
OUT
OUT
IN
OUT
136
88
0
0
1
0
IN
IN
OUT
OUT
131
83
1
1
0
0
OUT
IN
OUT
OUT
130
82
0
1
0
0
IN
OUT
OUT
OUT
129
81
1
0
0
0
OUT
OUT
OUT
OUT
128
80
0
0
0
0
CL
B
CU
A
DEC
HEX
D0
D1
D3
D4
NOTE:
D7 is always 1; D6, D5, and D2 are always 0.
6.1.12 CONVERT DISABLE REGISTER
BASE ADDRESS + 404h
T
T
T
T
T
T
T
T
0
1
2
3
4
5
6
7
WRITE ONLY. Writing a 0 to this register enables triggering of the A/D converter if the DAS1600
mode is enabled. On power-up or reset this register is reset to conversion triggers enabled. Writing a
40 hex to this register disables A/D conversions.
6.1.13 BURST MODE ENABLE REGISTER
BASE ADDRESS + 405h
B
B
B
B
B
B
B
B
0
1
2
3
4
5
6
7
WRITE ONLY. Burst mode enable. Writing 40 hex to this register enables the burst trigger. Writing 0
to this register disables burst trigger. On power-up or reset the burst trigger is disabled.
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