Pulse Width Measurement - Toshiba TLCS-900/H1 Series Manual

Original cmos 32-bit microcontroller

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Pulse width measurement

This mode allows measuring 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 TB0IN0 pin. Then the capture

function is used to load the UC10 values into TB0CP0H/L and TB0CP1H/L at the

rising edge and falling edge of the external trigger pulse respectively. The

interrupt INT6 occurs at the falling edge of TB0IN0.

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

TB0CP0H/L and TB0CP1H/L and the internal clock cycle.

For example, if the internal clock is 0.8[us] and the difference between

TB0CP0H/L and TB0CP1H/L is 100, the pulse width will be 100 × 0.8[μs] =80μs

Additionally, the pulse width which is over the UC10 maximum count time

specified by the clock source can be measured by changing software.

(Prescaler ouptut clock)

TB0IN0 pin input

(External pulse)

Loading to TB0CP0H/L

Loading to TB0CP1H/L

Note: Only in this pulse width measuring mode(TB0MOD<TB0CPM1:0>= "10"), external interrupt INT6 occurs at the

falling edge of TB0IN0 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 C1 and the second C0 at the second INT6 interrupt and the internal clock

cycle together.

Figure 3.13.14 Pulse Width Measurement