TMP93CS41 datasheet(153/248 Pages) TOSHIBA

153 / 248 page

TMP93CS40/TMP93CS41

2004-02-10

93CS40-151

3. Pulse width measurement

This mode allows measurement of 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 via the TI4 pin. Then the capture function is used to load the UC4

values into CAP1 and CAP2 on 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

µs and the difference between CAP1 and CAP2 is

100, the pulse width will be 100

× 0.8 µs = 80 µs.

Figure 3.9.18 Pulse Width Measurement

Note:

External interrupt INT4 occurs at the falling edge of the TI4 pin input only in this pulse

width measuring mode (T4MOD<CAP12M1:0> = 10). In other modes, it occurs at the

rising edge.

The width of the L level can be measured from the difference between the first C2 and the

second C1 at the second INT4 interrupt.

4. Time difference measurement

This mode is used to measure the difference in time between the rising edges of external

pulses input via TI4 and TI5.

While keeping the 16-bit timer/event counter (Timer 4) counting (Free running) with the

internal clock, the UC4 value is loaded into CAP1 on the rising edge of the input pulse to

TI4. Then the interrupt INT4 is generated.

Similarly, the UC4 value is loaded into CAP2 on the rising edge of the input pulse to TI5,

generating the interrupt INT5.

The time difference between these pulses can be obtained from the difference between

the time counts at which loading the up counter value into CAP1 and CAP2 was performed.

Count clock

(Internal clock)

TI4 pin

(External pulse)

Loading UC4 into CAP1

Loading UC4 into CAP2

INT4

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