Zenith Z-100 PC series Service Manual page 98

Page
4-12
Detailed Circuit Description
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Figure 4-6: Programmable Interval Timer Pinouts
Table 4-5: Programmable Interval Timer Programming Codes
INPUT SIGNALS
CS* RD* WR* AO AI FUNCTION
0
1
0 0 0 Load counter 0
0 1 0 0 1 Load counter 1
0 1 0 I 0 Load counter 2
0 1 0 1 1 Write mode word
0 0 1 0 0 Read counter 0
0 0
1
0 I
Read counter I
0 0
1
0 Read coun ter 2
0 0 1
1
No opera tion 3-state
1 x x x x
Disabled 3-sta te
0 1 I x x No-operation 3-state