4. Functions
50
CNT32-4MT(LPCI)
Obtaining the count value
Obtaining the count value
There are two modes for obtaining the count value. One is the counter mode to directly read the count
value without using bus mastering and the other is the sampling mode to sample the count value
periodically using bus mastering.
This board is capable of bus mastering, enabling periodical sampling of the count value using the
internal or external clock signal.
Is a sampling used?
Bus mastering is not used.
Only counter start/stop is used.
Sampling start/stop cannot be used.
Counter mode
Bus mastering is used.
Both of counter start/stop and sampling start/stop are used.
Counting and sampling can be performed synchronously
by specifying sampling start/stop as the counter start/stop condition
.
Sampling mode
Yes
No
Figure 4.8. Counter mode and sampling mode
Counter mode
In the counter mode, the board starts the counter after setting counter operation conditions and performs
counter operations such as reading the count value and status.
In addition, this mode allows the board to preset, zero-clear, start/stop the counter at the rising or falling
edge of the control input signal. A one-shop pulse can be output to the control input signal at an
occurrence of a count match or error.
Pulse input signal
Sampling clock
Count value
0
1
2
3
4
5
6
7
8
9
Nothing
Sampling value
Nothing
Nothing
Nothing
Counter start
Counter stop
Figure 4.9. Timing chart (Counter mode)
