Toshiba PROSEC T3 User Manual page 75

(5) Operation
PI312 generates an interrupt every specified interval time. The interval time is
measured by counting PI312's internal clock pulses. The frequency of the internal
clock can be selected from 1, 10 or 100 kHz.
In the normal count mode, PI312 counts at the rising edge of the internal clock pulse.
On the other hand, in the precision count mode, PI312 counts at both rising and falling
edges of the internal clock pulse. The table below shows the time units which
increases the count value by 1.
Count
mode
Normal
Precision
This mode function is enabled while both phase G and soft-gate are ON. (even when
the either is OFF, counting is not stopped)
When the count value reaches the set-point-1, the count value is reset to 0 (zero).
The set-point-1 can be set in the range of 1 to 16777215.
When the interrupt-enable bit in the command register (YW) is ON, PI312's interrupt
function is enabled. In this condition, when the count value reaches the set-point-1,
the PI312 generates interrupt signal for the T3. Therefore PI312 functions as cyclic
interrupt generator.
For example, when the set-point-1 is 285 in 10 kHz normal count mode, the PI312
generates interrupt every 28.5 ms.
When phase G or soft-gate comes OFF, the current count value is transferred into the
hold register.
Internal clock Time units (= 1 count)
1 kHz 1 ms
10 kHz 0.1 ms
100 kHz 0.01 ms
1 kHz 0.5 ms
10 kHz 0.05 ms
100 kHz 0.005 ms
6. Function Details
73
User's Manual