Advantech PCL-818L, Руководство пользователя

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52 PCL-818L User's Manual
BCD Select binary or BCD counting.
BCD Type
0 Binary counting 16-bits
1 Binary coded decimal (BCD) counting
If you set the module for binary counting, the count can be any
number from 0 up to 65535. If you set it for BCD (Binary Coded
Decimal) counting, the count can be any number from 0 to 9999.
If you set both SC1 and SC0 bits to 1, the counter control register is in
read-back command mode. The control register data format then
becomes:
BASE+15 – 8254 control, read-back mode
Bit
D7 D6 D5 D4 D3 D2 D1 D0
Value 1 1 CNT STA C2 C1 C0 X
CNT = 0 Latch count of selected counter(s).
STA = 0 Latch status of selected counter(s).
C2, C1 & C0 Select counter for a read-back operation.
C2 = 1 select Counter 2
C1 = 1 select Counter 1
C0 = 1 select Counter 0
If you set both SC1 and SC0 to 1 and STA to 0, the register selected by
C2 to C0 contains a byte which shows the status of the counter. The
data format of the counter read/write register then becomes:
BASE+12/13/14 – status read-back mode
Bit D7 D6 D5 D4 D3 D2 D1 D0
Value OUT NC RW1 RW0 M2 M1 M0 BCD