Input Capture Mode - Renesas R8C Series User Manual

R8C/1A Group, R8C/1B Group
14.3.1

Input Capture Mode

In input capture mode, the edge of the TCIN pin input signal or the fRING128 clock is used as a trigger to latch
the timer value and generate an interrupt request. The TCIN input contains a digital filter, and this prevents
errors caused by noise or the like from occurring. Table 14.11 shows the Input Capture Mode Specifications.
Figure 14.30 shows an Operating Example in Input Capture Mode.
Table 14.11 Input Capture Mode Specifications
Item
Count sources
Count operations
Count start condition
Count stop condition
Interrupt request
generation timing
INT3/TCIN pin function
P1_0 to P1_2, P3_3 to
P3_5 pin functions
Counter value reset timing When the TCC00 bit in the TCC0 register is set to 0 (count stops).
(2)
Read from timer
Write to timer
Select functions
NOTES:
1. The INT3 interrupt includes a digital filter delay and one count source (max.) delay.
2. Read registers TC and TM0 in 16-bit unit.
Rev.1.30 Dec 08, 2006
REJ09B0252-0130
f1, f8, f32, fRING-fast
• Increment
• Transfer the value in the TC register to the TM0 register at the active edge
of the measured pulse.
• The value in the TC register is set to 0000h when the count stops.
The TCC00 bit in the TCC0 register is set to 1 (count starts).
The TCC00 bit in the TCC0 register is set to 0 (count stops).
• When the active edge of the measured pulse is input [INT3 interrupt].
• When timer C overflows [timer C interrupt].
Programmable I/O port or the measured pulse input (INT3 interrupt input)
Programmable I/O port
• The count value can be read out by reading the TC register.
• The count value at the measured pulse active edge input can be read out
by reading the TM0 register.
Write to the TC and TM0 registers is disabled.
• INT3/TCIN polarity select function
Bits TCC03 to TCC04 can select the active edge of the measured pulse.
• Digital filter function
Bits TCC11 to TCC10 can select the digital filter sampling frequency.
• Trigger select function
The TCC07 bit can select the TCIN input or the fRING128.
Page 147 of 315
Specification
14. Timers
(1)