rtd DM6210, Руководство пользователя

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4-6
BA + 7: Reserved.
BA + 8: 8254 TC Counter 0 (Read/Write 8-bit)
This address is used to read/write the 8254 TC Counter 0. A read shows the count in the counter, and a
write loads the counter with a new value. Counting begins as soon as the count is loaded.
BA + 9: 8254 TC Counter 1 (Read/Write 8-bit)
This address is used to read/write the 8254 TC Counter 1. A read shows the count in the counter, and a
write loads the counter with a new value. Counting begins as soon as the count is loaded.
BA + 10: 8254 TC Counter 2 (Read/Write 8-bit)
This address is used to read/write the 8254 TC Counter 2. A read shows the count in the counter, and a
write loads the counter with a new value. Counting begins as soon as the count is loaded.
BA + 11: 8254 Control Word (Write Only 8-bit)
This address is used to write to the control register for the 8254. The control word is defined below and
detailed in the data sheet included in Appendix C.
' ' ' ' ' ' ' '
Counter Select
00 = Counter 0
01 = Counter 1
10 = Counter 2
11 = read back setting
BCD/Binary
0 = binary
1 = BCD
Counter Mode Select
000 = Mode 0, event count
001 = Mode 1, programmable 1-shot
010 = Mode 2, rate generator
011 = Mode 3, square wave rate generator
100 = Mode 4, software-triggered strobe
101 = Mode 5, hardware-triggered strobe
Read/Load
00 = latching operation
01 = read/load LSB only
10 = read/load MSB only
11 = read/load LSB, then MSB