TMP88CS77F datasheet(66/140 Pages) TOSHIBA

66 / 140 page

3-77-66

TMP88CP77/S77/U77

2007-10-23

(4) Window mode

Counting up is performed on the rising edge of the pulse that is the logical AND-ed product of the TC1

pin input (window pulse) and an internal clock. The contents of TREG1A are compared with the

contents of up-counter. If a match is found, an INTTC1 interrupt is generated, and the counter is

cleared. Positive or negative logic for the TC1 pin input can be selected. Edge selection is the same as

for INT2 pin. Setting SCAP1 to “1” transfers the current contents of up-counter to TREG1B.

It is necessary that the maximum applied frequency be such that the counter value can be analyzed by

the program. That is; the frequency must be considerably slower than the selected internal clock.

Figure 2-23. Window Mode Timing Chart

(5) Pulse width measurement mode

Counting is started by the external trigger (set to external trigger start by TC1S). The trigger can be

selected either the rising or falling edge of the TC1 pin input. The source clock is used an internal clock.

On the next falling (rising) edge, the counter contents are transferred to TREG1B and an INTTC1

interrupt is generated. The counter is cleared when the single edge capture mode is set. When double

edge capture is set, the counter continues and, at the next rising (falling) edge, the counter contents

are again transferred to TREG1B. If a falling (rising) edge capture value is required, it is necessary to

read out TREG1B contents until a rising (falling) edge is detected. Falling or rising edge is selected with

INT2ES, and single edge or double edge is selected with MCAP1 (bit 6 in TC1CR).

Note:

The first captured value after the timer starts may be read incorrectively, therefore, ignore the

first captured value.

Match detect

TREG1A

INTTC1 interrupt

Internal clock

Up-counter

TREG1A

TC1 pin input

Internal clock

Up-counter

TC1 pin input

INTTC1 interrupt

(a) Positive logic (at INT2ES=0)

(b) Negative logic (at INT2ES=1)

Match detect

Counter clear

Command start

Counter clear

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