r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 257

• Manufacturer Part Number: r5f21346mnfp
• Description: Single-chip Mcus Incorporates The R8c Cpu Core
• Manufacturer: Renesas Electronics Corporation.

R8C/34M Group
R01UH0131EJ0100 Rev.1.00
Jun 21, 2011
17.7
Table 17.6
Note:
Count sources
Count operations
Count start condition
Count stop conditions
Interrupt request
generation timing
TRAIO pin function
TRAO pin function
Read from timer
Write to timer
Selectable functions
In pulse period measurement mode, the pulse period of an external signal input to the TRAIO pin is measured
(refer to Table 17.6 Pulse Period Measurement Mode Specifications).
Figure 17.4 shows an Operating Example of Pulse Period Measurement Mode.
1. Input a pulse with a period longer than twice the timer RA prescaler period. Input a pulse with a
longer “H” and “L” width than the timer RA prescaler period. If a pulse with a shorter period is input
to the TRAIO pin, the input may be ignored.
Pulse Period Measurement Mode
Item
Pulse Period Measurement Mode Specifications
f1, f2, f8, fOCO, fC32, fC
• After the active edge of the measured pulse is input, the contents of the read-
1 (count starts) is written to the TSTART bit in the TRACR register.
• 0 (count stops) is written to TSTART bit in the TRACR register.
• 1 (count forcibly stops) is written to the TSTOP bit in the TRACR register.
• When timer RA underflows or reloads [timer RA interrupt].
• Rising or falling of the TRAIO input (end of measurement period) [timer RA
Measured pulse input
• When registers TRAPRE and TRA are written while the count is stopped,
• When registers TRAPRE and TRA are written during the count, values are
• Measurement period selection
• Measured pulse input pin select function
• Digital filter function
• Decrement
Programmable I/O port
The count value can be read by reading registers TRA and TRAPRE.
out buffer are retained at the first underflow of timer RA prescaler. Then timer
RA reloads the contents in the reload register at the second underflow of
timer RA prescaler and continues counting.
interrupt]
values are written to both the reload register and counter.
written to the reload register and counter (refer to 17.3.2 Timer Write
Control during Count Operation ).
The measurement period of the input pulse is selected by the TEDGSEL in
the TRAIOC register.
P1_5 or P1_7 is selected by bits TRAIOSEL0 to TRAIOSEL1 in the TRASR
register.
Whether enabling or disabling the digital filter and the sampling frequency is
selected by bits TIPF0 and TIPF1 in the TRAIOC register.
(1)
Specification
Page 225 of 740
17. Timer RA