Kontron 104-AD128, User Manual

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5-10
104-ADIO128 (AD128) User’s Guide
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Using the Counter/Timer Circuit
We suggest using mode 2, rate generator, for timer ticks and for timer triggered events. Note
that the outputs of the counters go high when each counter’s command is written to the
Counter/Timer chip. Please see the 82C54 datasheet in the \ChipDocs directory.
Table 5-3. Control Word
For bits 7 and 6:
00 = select counter 0, 01= select counter 1, 10 = select counter 2, 11 = read back
For bits 5 and 4:
0,0 = counter latch, 01= read/write LSB, 10 = read/write MSB, 11 = read/write LSB MSB
For bits 3, 2, and 1:
000 = mode 0, 001 = mode 1, 10 = mode 2, 11 = mode 3, 100 = mode 4, 101 = mode 5
For bit 0:
0 = 16 bit binary, 1 = binary coded decimal
Bit Write
Bit 0 Binary Coded Decimal
Bit 1 Mode Selection Bit 0
Bit 2 Mode Selection Bit1
Bit 3 Mode Selection Bit2
Bit 4 Mode Selection 0
Bit 5 Read/Write Selection Bit1
Bit 6 Counter Selection Bit0
Bit 7 Counter Selection Bit1