TMP93CS32F datasheet(107/180 Pages) TOSHIBA

107 / 180 page

TMP93CS32

2004-02-10

93CS32-105

3. Pulse width measurement

This mode allows to measure the “H” level width of an external pulse. While keeping

the 16-bit timer/event counter counting (free-running) with the internal clock input,

the external pulse is input through the TI4 pin. Then the capture function is used to

load the UC4 values into CAP1 and CAP2 at the rising edge and falling edge of the

external trigger pulse respectively. The interrupt INT4 occurs at the falling edge of

TI4.

The pulse width is obtained from the difference between the values of CAP1 and

CAP2 and the internal clock cycle.

For example, if the internal clock is 0.8 microseconds and the difference between

CAP1 and CAP2 is 100, the pulse width will be 100

× 0.8 µs = 80 µs.

Additionally, the pulse width which is over the UC4 maximum count time specified

by the clock source can be measured by changing software.

Figure 3.8.16 Pulse Width Measurement

Note:

Only in this pulse width measuring mode (T4MOD<CAP12M1:0> = 10), external

interrupt INT4 occurs at the falling edge of TI4 pin input. In other modes, it occurs

at the rising edge.

The width of “L” level can be measured by multiplying the difference between the

first C2 and the second C1 at the second INT4 interrupt and the internal clock cycle

together. See Figure 3.8.17 Time Difference Measurement.

TI4 pin

(External pulse)

Loading UC4 into CAP1

Count clock

(Internal clock)

Loading UC4 into CAP2

INT4

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