r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 259

• 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
Figure 17.4
17.7.2
Conditions: The period from one rising edge to the next rising edge of the measured pulse is measured (TEDGSEL = 0) with
the default value of the TRA register as 0Fh.
Notes:
1. The contents of the read-out buffer can be read by reading the TRA register in pulse period measurement mode.
2. After an active edge of the measured pulse is input, the TEDGF bit in the TRACR register is set to 1 (active edge received) when the
3. The TRA register should be read before the next active edge is input after the TEDGF bit is set to 1 (active edge received).
4. To set to 0 by a program, use a MOV instruction to write 0 to the TEDGF bit in the TRACR register. At the same time, write 1 to the
5. To set to 0 by a program, use a MOV instruction to write 0 to the TUNDF bit. At the same time, write 1 to the TEDGF bit.
6. Bits TUNDF and TEDGF are both set to 1 if timer RA underflows and reloads on an active edge simultaneously.
timer RA prescaler underflows for the second time.
The contents in the read-out buffer are retained until the TRA register is read. If the TRA register is not read before the next active edge
is input, the measured result of the previous period is retained.
TUNDF bit in the TRACR register.
Contents of read-out
Measurement pulse
Underflow signal of
timer RA prescaler
(TRAIO pin input)
Contents of TRA
TRACR register
TRACR register
TRACR register
IR bit in TRAIC
Operating Example
TSTART bit in
TEDGF bit in
TUNDF bit in
Operating Example of Pulse Period Measurement Mode
buffer
register
(1)
Count start
Set to 1 by program
0Fh
0Fh
0Eh 0Dh 0Fh 0Eh 0Dh 0Ch 0Bh 0Ah 09h 0Fh 0Eh 0Dh
0Eh
(Note 2)
Retained
TRA reloaded
0Dh
TRA read
Set to 0 when interrupt request is acknowledged, or set by program
Set to 0 by program
(3)
0Bh 0Ah
(Note 2)
Retained
(Note 4)
TRA reloaded
09h
0Dh
Set to 0 by program
01h 00h 0Fh 0Eh
01h 00h 0Fh 0Eh
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(Note 6)
17. Timer RA
Underflow
(Note 5)