tmp19a44fda TOSHIBA Semiconductor CORPORATION, tmp19a44fda Datasheet - Page 324

• Manufacturer Part Number: tmp19a44fda
• Description: 32bit Tx System Risc
• Manufacturer: TOSHIBA Semiconductor CORPORATION

16-bit Timer/Event Counters (TMRBs)
Prescaler output clock
TB6IN0 pin input
(External pulse)
Taking data into TB6CP0
Taking data into TB6CP1
INT4
Pulse width measurement
By using the capture function, the "H" level width of an external pulse can be measured. Specifically, an
external pulse is input through the TB0IN0 pin, and the up-counter (UC6) is made to count up by
putting it in a free-running state using the prescaler output clock. A trigger is generated at each rising
and falling edge of the external pulse by using the capture function and the value of the up-counter is
taken into the capture registers (TB6CP0, TB6CP1). The INTC must be programmed so that INT4 is
generated at the falling edge of an external pulse input through the TB6IN0 pin.
The "H" level pulse width can be calculated by multiplying the difference between TB6CP0 and
TB6CP1 by the clock cycle of an internal clock.
For example, if the difference between TB6CP0 and TB6CP1 is 100 and the cycle of the prescaler
output clock is 0.5 μs, the "H" level pulse width is 100 × 0.5 μs = 50 μs.
Caution must be exercised when measuring pulse widths exceeding the UC6 maximum count time
which is dependant upon the source clock used. The measurement of such pulse widths must be made
using software.
The "L" level width of an external pulse can also be measured. In such cases, the difference between
C2 generated the first time and C1 generated the second time is initially obtained by performing the
second stage of INT4 interrupt processing as shown in Fig. 11.78 and this difference is multiplied by the
cycle of the prescaler output clock to obtain the "L" level width.
C1
Fig. 11.8 Pulse Width Measurement
C1
TMP19A44(rev1.3) 11-26
C2
C2
C1
TMP19A44
C2
2010-04-01