Contec CNT-3204MT-LPE, Руководство пользователя

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4. Functions
CNT-3204MT-LPE
55
Count match
Functions are provided to generate an interrupt, externally output a one-shot pulse, preset the counter
value, or clear the counter to zero when the count matches the value in compare register 0 or compare
register 1.
This product has two compare registers for each channel used to compare the count value. If two or
more registers are required, use software to update the register values. Having two compare registers
available allows upper and lower limits to be set.
Table 4.9. Count match
Item Factor Function
Count match Count value = Comparison register 0 or
Count value = Comparison register 1
Interrupt
One-shot pulse output
Preset
Zero-clear
Given below are application examples using the count match feature.
< Example 1 > Move count values 100 - 200 in both ways. When the count value falls below 90 or
exceeds 210, a one-shot pulse is output to an external device.
Figure 4.13. Example 1
Initial setting
External output signal selection:Count match 0 or Count match 1
Channel 0 Comparison register 1 = 210
Channel 0 Comparison register 0= 90
Channel 0 Preset register = 100
Event at (1) (Agrees with comparison register 0)
- A one-shot pulse is output with count value = comparison register 0.
210
200
100
90
Counter start
(1)
(2)
Event at (2) (Agrees with comparison register 1)
- A one-shot pulse is output with count value = comparison register 1.