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PIO-D48 Series Card
48-channel OPTO-22 Compatible DIO Board
User Manual/Ver. 3.4/Aug. 2015/PMH-006-34/Page: 43
6.3.6 Read/Write 8254
8254 Control Word
(Read/Write): wBase+0xec
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
SC1
SC0
RL1
RL0
M2
M1
M0
BCD
BCD
0
Binary Count
1
BCD Count
M2 M1 M0
0
0
0
Interrupt on terminal count
0
0
1
Programmable one-shot
0
1
0
Rate generator
0
1
1
Square-wave generator
1
0
0
software triggered pulse
1
0
1
Hardware triggered pulse
RL1 RL0
0
0
Counter latch instruction
0
1
Read/write low counter byte only
1
0
Read/write high counter byte only
1
1
Read/write low counter byte first, then high counter
SC1 SC0
0
0
Counter0
0
1
Counter1
1
0
Counter2
1
1
Readback command